added ** for doc autogen.

src/objective-c/ProtoRPC/ProtoRPC.h

@@ -38,7 +38,7 @@
 
 @interface ProtoRPC : GRPCCall
 
-/*
+/**
  * host parameter should not contain the scheme (http:// or https://), only the name or IP addr
  * and the port number, for example @"localhost:5050".
  */