docs: Turn off section numbering for the input docs

The input docs enable section numbering at multiple levels, leading to a
lot of bright-red "nested numbered toctree" warnings in newer Sphinx
versions.  Just take that directive out for now to help alleviate the
global red-pixel shortage.
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

Documentation/input/index.rst

@@ -6,7 +6,6 @@ Contents:
 
 .. toctree::
    :maxdepth: 2
-   :numbered:
 
    input_uapi
    input_kapi