Edited the 'Flushing HTTP requests' section

Minor grammatical edits in the Flushing HTTP requests section.

src/ngMock/angular-mocks.js

@@ -989,18 +989,18 @@ angular.mock.dump = function(object) {
  *
  * # Flushing HTTP requests
  *
- * The $httpBackend used in production, always responds to requests with responses asynchronously.
- * If we preserved this behavior in unit testing, we'd have to create async unit tests, which are
- * hard to write, follow and maintain. At the same time the testing mock, can't respond
+ * The $httpBackend used in production always responds to requests with responses asynchronously.
+ * If we preserved this behavior in unit testing we'd have to create async unit tests, which are
+ * hard to write, understand, and maintain. However, the testing mock can't respond
  * synchronously because that would change the execution of the code under test. For this reason the
  * mock $httpBackend has a `flush()` method, which allows the test to explicitly flush pending
- * requests and thus preserving the async api of the backend, while allowing the test to execute
+ * requests and thus preserve the async api of the backend while allowing the test to execute
  * synchronously.
  *
  *
  * # Unit testing with mock $httpBackend
- * The following code shows how to setup and use the mock backend in unit testing a controller.
- * First we create the controller under test
+ * The following code shows how to setup and use the mock backend when unit testing a controller.
+ * First we create the controller under test:
  *
   <pre>
   // The controller code
@@ -1025,7 +1025,7 @@ angular.mock.dump = function(object) {
   }
   </pre>
  *
- * Now we setup the mock backend and create the test specs.
+ * Now we setup the mock backend and create the test specs:
  *
   <pre>
     // testing controller