docs: verify/bisect: Fix rendered version URL

When rendering the documentation, the 'html' file extension replaces the
'rst' file extension, not add it. So remove the 'rst' part of the URL.

Signed-off-by: Diederik de Haas <didi.debian@cknow.org>
Reviewed-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240620081355.11549-1-didi.debian@cknow.org