DOCS(protocol): Add file references to README.rst

docs/dev/network-protocol/README.rst

@@ -5,3 +5,8 @@ The Mumble Network Protocol documentation is meant to be a reference for the
 Mumble VoIP 1.2.X server-client communication protocol. It reflects the state of
 the protocol implemented in the Mumble 1.2.8 client and might be outdated by the
 time you are reading this.
+
+* `Overview <overview.rst>`_
+* `Protocol Stack (TCP) <protocol_stack_tcp.rst>`_
+* `Establishing a Connection <establishing_connection.rst>`_
+* `Voice Data <voice_data.rst>`_