Merge pull request AFNetworking#3476 from ecaselles/ecaselles-update-methods-override-documentation

Updates `AFHTTPSessionManager` documentation to reflect v3.x changes

Author: kcharwood

AFNetworking/AFHTTPSessionManager.h

@@ -44,7 +44,7 @@
 
  ## Methods to Override
 
- To change the behavior of all data task operation construction, which is also used in the `GET` / `POST` / et al. convenience methods, override `dataTaskWithRequest:completionHandler:`.
+ To change the behavior of all data task operation construction, which is also used in the `GET` / `POST` / et al. convenience methods, override `dataTaskWithRequest:uploadProgress:downloadProgress:completionHandler:`.
 
  ## Serialization