docs: filesystems: Remove uneeded .rst extension on toctables

There's no need to use a .rst on Sphinx toc tables. As most of
the Documentation don't use, remove the remaing occurrences.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/Documentation/filesystems/index.rst b/Documentation/filesystems/index.rst
index 3564484..1651173 100644
--- a/Documentation/filesystems/index.rst
+++ b/Documentation/filesystems/index.rst
@@ -17,7 +17,7 @@
    :maxdepth: 2
 
    vfs
-   path-lookup.rst
+   path-lookup
    api-summary
    splice
 
@@ -41,4 +41,4 @@
 .. toctree::
    :maxdepth: 2
 
-   binderfs.rst
+   binderfs