Doc: how to make the CI look green

[LecrisUT]

This is orthogonal with what this action does, but it is a common consequence of using this action, namely how do we report on the top page that the current CI was successful? Some candidates:

• is there a badge to report the specific alls-green status? This is not ideal because the commit is still reported with a cross
• ~~document using steps.<step_id>.outcome + another step with exit 0 to overwrite the exit status. Haven't confirmed that this works, but it could be useful to overwrite the CI status when on.push, while when on on.pull_request keep the normal report~~. This is still a lost cause as far as I've tested
• within a reusable workflow, could one use all-green to overwrite the job outcome of the workflow job that calls uses? When I've tried to use it, the workflow diagram can get a bit mesy, even though the documentation suggests that they should be compressed. Some tips for people using this design would be good

Upvote & Fund

• We're using Polar.sh so you can upvote and help fund this issue.
• We receive the funding once the issue is completed & confirmed by you.
• Thank you in advance for helping prioritize & fund our backlog.