gitlab-ci: Extend .ci-run-policy template for docs jobs

Requires using rules: in the pages job as well, so it doesn't inherit
the rules from the template.

v2:
* Add comment explaining that cases not covered by explicit rules
  default to "when: never".

Reviewed-by: Daniel Stone <daniels@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5469>
1 file changed