Closing issues when comment is removed

[villiamriegler]

Suggestion

As we already store all open issues in memory, simply close all issues labeled TODO where no matching comment was found.

Elaboration

The problematic part would be if the action is run on multiple branches with different comments, in that case, we would have to look through the code in all branches that the action currently cannot access. Using the previous approach of pulling files via the API would however allow this.

Perhaps allowing users to opt into this functionality would be the best approach, as we also don't want to remove issues that aren't fixed just because the comment is removed.