add closed-issues and move epic to compatible

[mbertucci47]

Adds closed-issues to the YAML file and moves epic to compatible. I don't know if the HTML conversion will just ignore the unknown type or if something needs to be done there.

[davidcarlisle]

The closed-issues field is currently simply ignored. If we want to show it but with different styling I'd need to copy/modify the exiting display for the issues field, but I think ignoring is OK for now.

[FrankMittelbach]

The closed-issues field is currently simply ignored. If we want to show it but with different styling I'd need to copy/modify the exiting display for the issues field, but I think ignoring is OK for now.

agreed, but perhaps we should show them in the full table in a separate column

[davidcarlisle]

@FrankMittelbach added, see https://latex3.github.io/tagging-project/tagging-status/full#acro not as a separate column as that would eat too much space, the issues column already shows several separate lists for issues in this repo, issues elsewhere etc so I added a list of closed issues (with strikethrough style)

[FrankMittelbach]

the strikethrough is not really visible for me with my current browser settings, but it works well enough given the intro "Closed:"