MAINTAINERS: update filter of FUSE documentation

There are some fuse-*.rst files in Documentation directory,
let's make get_mantainers.pl work on those file instead of only
fuse.rst.

Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Chen Linxuan <chenlinxuan@uniontech.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>