Moved docs related changes from metadatasource-cleanup

Author: semohr

docs/dev/index.rst

@@ -4,15 +4,16 @@ For Developers
 This section contains information for developers. Read on if you're interested
 in hacking beets itself or creating plugins for it.
 
-See also the documentation for `MediaFile`_, the library used by beets to read
-and write metadata tags in media files.
+See also the documentation for the `MediaFile`_ and `Confuse`_ libraries. These are maintained by the beets team and used to read and write metadata tags and manage configuration files, respectively.
 
 .. _MediaFile: https://mediafile.readthedocs.io/en/latest/
+.. _Confuse: https://confuse.readthedocs.io/en/latest/
+
 
 .. toctree::
     :maxdepth: 1
 
-    plugins
+    plugins/index
     library
     importer
     cli