docs: Note that :c:func: should no longer be used

Now that we can mark up function() automatically, there is no reason to use
:c:func: and every reason to avoid it.  Adjust the documentation to reflect
that fact.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Jonathan Corbet 2019-06-26 11:20:21 -06:00
commit d9d7c0c497