Use `check_run` output annotations to link to action item lines

[NikkelM]

The update a check run API call includes the option of setting annotations in the output. We should investigate if these may be a replacement for the comment the app posts.
See the list check run annotations for the output provided by this endpoint.

Note that only 50 annotations can be set per API call. If there are more pending action items, additional calls will need to be made.