docs(scope): clean up grammar and improve clarity

Some typos fixed and grammar improved:
- withing -> within
- life-cycle -> life cycle
- extraneous spaces
- grammar mistakes
- missing commas
- reworded unclear statements

Closes angular#3920

Author: sdornan

src/ng/rootScope.js

@@ -56,7 +56,7 @@
  *
  * Every application has a single root {@link ng.$rootScope.Scope scope}.
  * All other scopes are child scopes of the root scope. Scopes provide mechanism for watching the model and provide
- * event processing life-cycle. See {@link guide/scope developer guide on scopes}.
+ * event processing life cycle. See {@link guide/scope developer guide on scopes}.
  */
 function $RootScopeProvider(){
   var TTL = 10;
@@ -152,9 +152,9 @@ function $RootScopeProvider(){
        * the scope and its child scopes to be permanently detached from the parent and thus stop
        * participating in model change detection and listener notification by invoking.
        *
-       * @param {boolean} isolate if true then the scope does not prototypically inherit from the
+       * @param {boolean} isolate If true, then the scope does not prototypically inherit from the
        *         parent scope. The scope is isolated, as it can not see parent scope properties.
-       *         When creating widgets it is useful for the widget to not accidentally read parent
+       *         When creating widgets, it is useful for the widget to not accidentally read parent
        *         state.
        *
        * @returns {Object} The newly created child scope.
@@ -167,12 +167,12 @@ function $RootScopeProvider(){
         if (isolate) {
           child = new Scope();
           child.$root = this.$root;
-          // ensure that there is just one async queue per $rootScope and it's children
+          // ensure that there is just one async queue per $rootScope and its children
           child.$$asyncQueue = this.$$asyncQueue;
           child.$$postDigestQueue = this.$$postDigestQueue;
         } else {
           Child = function() {}; // should be anonymous; This is so that when the minifier munges
-            // the name it does not become random set of chars. These will then show up as class
+            // the name it does not become random set of chars. This will then show up as class
             // name in the debugger.
           Child.prototype = this;
           child = new Child();
@@ -202,7 +202,7 @@ function $RootScopeProvider(){
        * Registers a `listener` callback to be executed whenever the `watchExpression` changes.
        *
        * - The `watchExpression` is called on every call to {@link ng.$rootScope.Scope#$digest $digest()} and
-       *   should return the value which will be watched. (Since {@link ng.$rootScope.Scope#$digest $digest()}
+       *   should return the value that will be watched. (Since {@link ng.$rootScope.Scope#$digest $digest()}
        *   reruns when it detects changes the `watchExpression` can execute multiple times per
        *   {@link ng.$rootScope.Scope#$digest $digest()} and should be idempotent.)
        * - The `listener` is called only when the value from the current `watchExpression` and the
@@ -313,13 +313,13 @@ function $RootScopeProvider(){
        *
        * @description
        * Shallow watches the properties of an object and fires whenever any of the properties change
-       * (for arrays this implies watching the array items, for object maps this implies watching the properties).
-       * If a change is detected the `listener` callback is fired.
+       * (for arrays, this implies watching the array items; for object maps, this implies watching the properties).
+       * If a change is detected, the `listener` callback is fired.
        *
        * - The `obj` collection is observed via standard $watch operation and is examined on every call to $digest() to
        *   see if any items have been added, removed, or moved.
-       * - The `listener` is called whenever anything within the `obj` has changed. Examples include adding new items
-       *   into the object or array, removing and moving items around.
+       * - The `listener` is called whenever anything within the `obj` has changed. Examples include adding, removing,
+       *   and moving items belonging to an object or array.
        *
        *
        * # Example
@@ -356,8 +356,8 @@ function $RootScopeProvider(){
        *    `oldCollection` object is a copy of the former collection data.
        *    The `scope` refers to the current scope.
        *
-       * @returns {function()} Returns a de-registration function for this listener. When the de-registration function is executed
-       * then the internal watch operation is terminated.
+       * @returns {function()} Returns a de-registration function for this listener. When the de-registration function 
+       * is executed, the internal watch operation is terminated.
        */
       $watchCollection: function(obj, listener) {
         var self = this;
@@ -458,18 +458,17 @@ function $RootScopeProvider(){
        * firing. This means that it is possible to get into an infinite loop. This function will throw
        * `'Maximum iteration limit exceeded.'` if the number of iterations exceeds 10.
        *
-       * Usually you don't call `$digest()` directly in
+       * Usually, you don't call `$digest()` directly in
        * {@link ng.directive:ngController controllers} or in
        * {@link ng.$compileProvider#directive directives}.
-       * Instead a call to {@link ng.$rootScope.Scope#$apply $apply()} (typically from within a
-       * {@link ng.$compileProvider#directive directives}) will force a `$digest()`.
+       * Instead, you should call {@link ng.$rootScope.Scope#$apply $apply()} (typically from within a
+       * {@link ng.$compileProvider#directive directives}), which will force a `$digest()`.
        *
        * If you want to be notified whenever `$digest()` is called,
-       * you can register a `watchExpression` function  with {@link ng.$rootScope.Scope#$watch $watch()}
+       * you can register a `watchExpression` function with {@link ng.$rootScope.Scope#$watch $watch()}
        * with no `listener`.
        *
-       * You may have a need to call `$digest()` from within unit-tests, to simulate the scope
-       * life-cycle.
+       * In unit tests, you may need to call `$digest()` to simulate the scope life cycle.
        *
        * # Example
        * <pre>
@@ -610,8 +609,8 @@ function $RootScopeProvider(){
        * {@link ng.directive:ngRepeat ngRepeat} for managing the
        * unrolling of the loop.
        *
-       * Just before a scope is destroyed a `$destroy` event is broadcasted on this scope.
-       * Application code can register a `$destroy` event handler that will give it chance to
+       * Just before a scope is destroyed, a `$destroy` event is broadcasted on this scope.
+       * Application code can register a `$destroy` event handler that will give it a chance to
        * perform any necessary cleanup.
        *
        * Note that, in AngularJS, there is also a `$destroy` jQuery event, which can be used to
@@ -643,7 +642,7 @@ function $RootScopeProvider(){
        * @function
        *
        * @description
-       * Executes the `expression` on the current scope returning the result. Any exceptions in the
+       * Executes the `expression` on the current scope and returns the result. Any exceptions in the
        * expression are propagated (uncaught). This is useful when evaluating Angular expressions.
        *
        * # Example
@@ -678,19 +677,19 @@ function $RootScopeProvider(){
        *
        * The `$evalAsync` makes no guarantees as to when the `expression` will be executed, only that:
        *
-       *   - it will execute after the function that schedule the evaluation is done running (preferably before DOM rendering).
+       *   - it will execute after the function that scheduled the evaluation (preferably before DOM rendering).
        *   - at least one {@link ng.$rootScope.Scope#$digest $digest cycle} will be performed after `expression` execution.
        *
        * Any exceptions from the execution of the expression are forwarded to the
        * {@link ng.$exceptionHandler $exceptionHandler} service.
        *
-       * __Note:__ if this function is called outside of `$digest` cycle, a new $digest cycle will be scheduled.
-       * It is however encouraged to always call code that changes the model from withing an `$apply` call.
+       * __Note:__ if this function is called outside of a `$digest` cycle, a new `$digest` cycle will be scheduled.
+       * However, it is encouraged to always call code that changes the model from within an `$apply` call.
        * That includes code evaluated via `$evalAsync`.
        *
        * @param {(string|function())=} expression An angular expression to be executed.
        *
-       *    - `string`: execute using the rules as defined in  {@link guide/expression expression}.
+       *    - `string`: execute using the rules as defined in {@link guide/expression expression}.
        *    - `function(scope)`: execute the function with the current `scope` parameter.
        *
        */
@@ -721,7 +720,7 @@ function $RootScopeProvider(){
        * @description
        * `$apply()` is used to execute an expression in angular from outside of the angular framework.
        * (For example from browser DOM events, setTimeout, XHR or third party libraries).
-       * Because we are calling into the angular framework we need to perform proper scope life-cycle
+       * Because we are calling into the angular framework we need to perform proper scope life cycle
        * of {@link ng.$exceptionHandler exception handling},
        * {@link ng.$rootScope.Scope#$digest executing watches}.
        *
@@ -790,7 +789,7 @@ function $RootScopeProvider(){
        *
        *   - `targetScope` - `{Scope}`: the scope on which the event was `$emit`-ed or `$broadcast`-ed.
        *   - `currentScope` - `{Scope}`: the current scope which is handling the event.
-       *   - `name` - `{string}`: Name of the event.
+       *   - `name` - `{string}`: name of the event.
        *   - `stopPropagation` - `{function=}`: calling `stopPropagation` function will cancel further event
        *     propagation (available only for events that were `$emit`-ed).
        *   - `preventDefault` - `{function}`: calling `preventDefault` sets `defaultPrevented` flag to true.
@@ -833,7 +832,7 @@ function $RootScopeProvider(){
        *
        * @param {string} name Event name to emit.
        * @param {...*} args Optional set of arguments which will be passed onto the event listeners.
-       * @return {Object} Event object, see {@link ng.$rootScope.Scope#$on}
+       * @return {Object} Event object (see {@link ng.$rootScope.Scope#$on}).
        */
       $emit: function(name, args) {
         var empty = [],