docs(ngResource): document steps to skip default json serialization/deserialization

src/ngResource/resource.js

@@ -124,10 +124,16 @@ function shallowClearAndCopy(src, dst) {
  *     `{function(data, headersGetter)|Array.<function(data, headersGetter)>}` –
  *     transform function or an array of such functions. The transform function takes the http
  *     request body and headers and returns its transformed (typically serialized) version.
+ *     By default, transformRequest will contain one function that checks if the request data is
+ *     an object and serializes to using `angular.toJson`. To prevent this behavior, set
+ *     `transformRequest` to an empty array: `transformRequest: []`
  *   - **`transformResponse`** –
  *     `{function(data, headersGetter)|Array.<function(data, headersGetter)>}` –
  *     transform function or an array of such functions. The transform function takes the http
  *     response body and headers and returns its transformed (typically deserialized) version.
+ *     By default, transformResponse will contain one function that checks if the response looks like
+ *     a JSON string and deserializes it using `angular.fromJson`. To prevent this behavior, set
+ *     `transformResponse` to an empty array: `transformResponse: []`
  *   - **`cache`** – `{boolean|Cache}` – If true, a default $http cache will be used to cache the
  *     GET request, otherwise if a cache instance built with
  *     {@link ng.$cacheFactory $cacheFactory}, this cache will be used for