Documentation/rv: Fix dead link to monitor_synthesis.rst

Documentation/rv: Fix dead link to monitor_synthesis.rst

The file 'da_monitor_synthesis.rst' was renamed to 'monitor_synthesis.rst' in
commit f40a7c06020709
("Documentation/rv: Prepare monitor synthesis document for LTL inclusion").

Signed-off-by: Soham Metha <sohammetha01@gmail.com>
Fixes: f40a7c06020709 ("Documentation/rv: Prepare monitor synthesis document for LTL inclusion")
Acked-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20251204032452.9523-1-sohammetha01@gmail.com>