cleanup(di): changed an error message to be more descriptive

Author: vsavkin

modules/angular2/src/di/exceptions.js

@@ -106,7 +106,8 @@ export class NoAnnotationError extends Error {
   message:string;
   constructor(typeOrFunc) {
     super();
-    this.message = `Cannot resolve all parameters for ${stringify(typeOrFunc)}`;
+    this.message = `Cannot resolve all parameters for ${stringify(typeOrFunc)}.` +
+      ` Make sure they all have valid type or annotations.`;
   }
 
   toString() {

modules/angular2/test/di/injector_spec.js

@@ -100,7 +100,8 @@ export function main() {
 
     it('should throw when no type and not @Inject', function () {
       expect(() => Injector.resolveAndCreate([NoAnnotations])).toThrowError(
-        'Cannot resolve all parameters for NoAnnotations');
+        'Cannot resolve all parameters for NoAnnotations. '+
+        'Make sure they all have valid type or annotations.');
     });
 
     it('should cache instances', function () {