Mention intro before specs

specification/index.rst

@@ -12,13 +12,15 @@ https://github.com/matrix-org/matrix-doc/blob/master/scripts/gendoc.py as of
 revision ``{{git_version}}`` -
 https://github.com/matrix-org/matrix-doc/tree/{{git_rev}}.
 
+There is an `introduction and overview to the specification here <intro.html>`_.
+
 The following APIs are documented in this specification:
 
 - `Client-Server API <client_server.html>`_ version %CLIENT_RELEASE_LABEL% for writing Matrix clients.
 - `Server-Server API <server_server.html>`_ version %SERVER_RELEASE_LABEL% for writing servers which can federate with Matrix.
 - `Application Service API <application_service.html>`_ version %CLIENT_RELEASE_LABEL% for writing privileged plugins to servers.
 
-There is also an `introduction with overview <intro.html>`_, and some `appendices <appendices.html>`_.
+There are also some `appendices <appendices.html>`_.
 
 Any developments since the latest release can be found `here`__.