[guide] Add clarification to arrow functions

Clarify and correct explanation — to be consistent with section 7.1 (use named function expressions).

Author: jabacchetta

README.md

@@ -912,11 +912,11 @@ Other Style Guides
 ## Arrow Functions
 
   <a name="arrows--use-them"></a><a name="8.1"></a>
-  - [8.1](#arrows--use-them) When you must use function expressions (as when passing an anonymous function), use arrow function notation. eslint: [`prefer-arrow-callback`](http://eslint.org/docs/rules/prefer-arrow-callback.html), [`arrow-spacing`](http://eslint.org/docs/rules/arrow-spacing.html) jscs: [`requireArrowFunctions`](http://jscs.info/rule/requireArrowFunctions)
+  - [8.1](#arrows--use-them) When you must use an anonymous function (as when passing an inline callback), use arrow function notation. eslint: [`prefer-arrow-callback`](http://eslint.org/docs/rules/prefer-arrow-callback.html), [`arrow-spacing`](http://eslint.org/docs/rules/arrow-spacing.html) jscs: [`requireArrowFunctions`](http://jscs.info/rule/requireArrowFunctions)
 
     > Why? It creates a version of the function that executes in the context of `this`, which is usually what you want, and is a more concise syntax.
 
-    > Why not? If you have a fairly complicated function, you might move that logic out into its own function declaration.
+    > Why not? If you have a fairly complicated function, you might move that logic out into its own named function expression.
 
     ```javascript
     // bad