Make the button show that the ticket has been resolved

[MMK21Hub]

It's a bit weird having a "mark as resolved" button on resolved tickets:

idk if it's possible to edit the button properties, but if we can, we should probably disable it and change the text

[MMK21Hub]

Turns out that this is relatively complex to do, and disabled buttons aren't even possible. (See commit 1e97e79 for what I mean.) I won't be implementing this for now.