docs: fix some broken documentation references

Some documentation files received recent changes and are
pointing to wrong places.

Those references can easily fixed with the help of a
script:

	$ ./scripts/documentation-file-ref-check --fix

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/net/bridge/Kconfig b/net/bridge/Kconfig
index aa0d3b2..3625d6a 100644
--- a/net/bridge/Kconfig
+++ b/net/bridge/Kconfig
@@ -17,7 +17,7 @@
 	  other third party bridge products.
 
 	  In order to use the Ethernet bridge, you'll need the bridge
-	  configuration tools; see <file:Documentation/networking/bridge.txt>
+	  configuration tools; see <file:Documentation/networking/bridge.rst>
 	  for location. Please read the Bridge mini-HOWTO for more
 	  information.