Fix some TODOs in the code (also TypeScript-related) #2721

https://github.com/sindresorhus/refined-github/blob/master/test/page-detect.ts

• 1: TODO: resolve this exception. AVA doesn't run without reference

https://github.com/sindresorhus/refined-github/blob/master/test/utils.ts

• 1: TODO: resolve this exception. AVA doesn't run without reference

https://github.com/sindresorhus/refined-github/blob/master/source/features/quick-review-buttons.tsx

• 79: TODO: maybe data-disable-with can do this like it does for the generic "Comment" button

https://github.com/sindresorhus/refined-github/blob/master/source/features/revert-file.tsx

• 96: TODO: find this info on the page ("was this file created by this PR?")

https://github.com/sindresorhus/refined-github/blob/master/source/features/pr-filters.tsx

• 67: TODO: replace this with an API call