Displays viewed/total file count on GitLab merge request pages
Gives you an idea of your progress on a GitLab merge request, for when uncooperative colleagues make too many changes.
Edits the innerText of the 'Changes' pill with a count of items you've marked as viewed, e.g. '99/141'. The background colour will also progressively change between the GitLab 'closed' colour to the 'merged' colour, because I felt like using color-mix.
NOTE: This script patches localStorage.setItem and localStorage.removeItem to observe same-tab storage changes. The native storage event only fires in other tabs, so patching is necessary to react to GitLab marking files as viewed or unviewed in the current tab.
