qga/qapi-schema: Clean up documentation of guest-set-vcpus

The command's doc comment describes the argument, but it's not marked
up as such.  Easy enough to fix.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240205074709.3613229-9-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
1 file changed