docs($http): add more info about transform function

Author: IgorMinar

src/ng/http.js

@@ -283,10 +283,14 @@ function $HttpProvider() {
      *  - if XSRF prefix is detected, strip it (see Security Considerations section below)
      *  - if json response is detected, deserialize it using a JSON parser
      *
-     * To override these transformation locally, specify transform functions as `transformRequest`
-     * and/or `transformResponse` properties of the config object. To globally override the default
-     * transforms, override the `$httpProvider.defaults.transformRequest` and
-     * `$httpProvider.defaults.transformResponse` properties of the `$httpProvider`.
+     * To globally augment or override the default transforms, modify the `$httpProvider.defaults.transformRequest` and
+     * `$httpProvider.defaults.transformResponse` properties of the `$httpProvider`. These properties are by default an
+     * array of transform functions, which allows you to `push` or `unshift` a new transformation function into the
+     * transformation chain. You can also decide to completely override any default transformations by assigning your
+     * transformation functions to these properties directly without the array wrapper.
+     *
+     * Similarly, to locally override the request/response transforms, augment the `transformRequest` and/or
+     * `transformResponse` properties of the config object passed into `$http`.
      *
      *
      * # Caching