a bit more documentation for --config

docs/changelog.rst

@@ -23,6 +23,8 @@ Unrelated new stuff:
   command-line flag (``--group-albums``), and config option
   (:ref:`group_albums`) that lets you split apart albums that are mixed
   together in a single directory. Thanks to geigerzaehler.
+* A new ``--config`` command-line option lets you specify an additional
+  configuration file. Thanks again to geigerzaehler.
 
 Other little fixes:
 

docs/reference/cli.rst

@@ -305,8 +305,7 @@ import ...``.
 * ``-d DIRECTORY``: specify the library root directory.
 * ``-v``: verbose mode; prints out a deluge of debugging information. Please use
   this flag when reporting bugs.
-* ``-c /path/to/file``: read the configuration from this file.
-
+* ``-c FILE``: read a specified YAML configuration file.
 
 .. only:: man
 

docs/reference/config.rst

@@ -11,10 +11,11 @@ every aspect of its operation. To configure beets, you'll edit a file called
 * On OS X, you can also use ``~/Library/Application Support/beets/config.yaml``
   if you prefer that over the Unix-like ``~/.config``.
 * If you prefer a different location, set the ``BEETSDIR`` environment variable
-  to a path; beets will then look for a ``config.yaml`` in that directory.
-
-Additionally, you can specify a different configuration file to load by adding
-the ``--config /path/to/file`` option to the beets command line.
+  to a path; beets will then look for a ``config.yaml`` in that directory. Or
+  specify a different configuration file to load using the ``--config
+  /path/to/file`` option on the command line. (There's one caveat with the
+  last option: since the configuration is loaded after the command line is
+  parsed, it cannot currently be used to load new plugins.)
 
 The config file uses `YAML`_ syntax. You can use the full power of YAML, but
 most configuration options are simple key/value pairs. This means your config