Add object-based collective APIs to public docs

Adds these new APIs to the documentation

Differential Revision: [D25363279](https://our.internmc.facebook.com/intern/diff/D25363279/)

ghstack-source-id: 117965961
Pull Request resolved: #48909

docs/source/distributed.rst

@@ -384,16 +384,24 @@ Collective functions
 
 .. autofunction:: broadcast 
 
+.. autofunction:: broadcast_object_list
+
 .. autofunction:: all_reduce
 
 .. autofunction:: reduce
 
 .. autofunction:: all_gather
 
+.. autofunction:: all_gather_object
+
 .. autofunction:: gather
 
+.. autofunction:: gather_object
+
 .. autofunction:: scatter
 
+.. autofunction:: scatter_object_list
+
 .. autofunction:: reduce_scatter
 
 .. autofunction:: all_to_all