Fix incorrect autodelegation documentation

Fix incorrect autodelegation documentation

The docs suggested to account for git prefixes (a/, b/) using eg.
?/patchwork/views/*. My rules didn't work so I tried bare path
(patchwork/views/*) instead. Looking at the code, the prefix really is
striped away (filename = '/'.join(filename.split('/')[1:])). Fix the
documentation to reflect on what is really happening.

Signed-off-by: Veronika Kabatova <vkabatov@redhat.com>
[dja: see 7bb0ebd78ff7 ("parser: Add patch_get_filenames()")]
Signed-off-by: Daniel Axtens <dja@axtens.net>