docs($q): fix a few issues

src/ng/q.js

@@ -85,8 +85,8 @@
  * **Methods**
  *
  * - `then(successCallback, errorCallback)` – regardless of when the promise was or will be resolved
- *   or rejected calls one of the success or error callbacks asynchronously as soon as the result
- *   is available. The callbacks are called with a single argument the result or rejection reason.
+ *   or rejected, `then` calls one of the success or error callbacks asynchronously as soon as the result
+ *   is available. The callbacks are called with a single argument: the result or rejection reason.
  *
  *   This method *returns a new promise* which is resolved or rejected via the return value of the
  *   `successCallback` or `errorCallback`.
@@ -99,21 +99,21 @@
  *
  * # Chaining promises
  *
- * Because calling `then` api of a promise returns a new derived promise, it is easily possible
+ * Because calling the `then` method of a promise returns a new derived promise, it is easily possible
  * to create a chain of promises:
  *
  * <pre>
  *   promiseB = promiseA.then(function(result) {
  *     return result + 1;
  *   });
  *
- *   // promiseB will be resolved immediately after promiseA is resolved and its value will be
- *   // the result of promiseA incremented by 1
+ *   // promiseB will be resolved immediately after promiseA is resolved and its value
+ *   // will be the result of promiseA incremented by 1
  * </pre>
  *
  * It is possible to create chains of any length and since a promise can be resolved with another
  * promise (which will defer its resolution further), it is possible to pause/defer resolution of
- * the promises at any point in the chain. This makes it possible to implement powerful apis like
+ * the promises at any point in the chain. This makes it possible to implement powerful APIs like
  * $http's response interceptors.
  *
  *