Convert the whole codebase to TypeScript and make it strict #1735
Description
- Convert the remaining files to TypeScript:
https://github.com/sindresorhus/refined-github/tree/master/source/libs
https://github.com/sindresorhus/refined-github/tree/master/source - Enable strict mode: https://github.com/sindresorhus/refined-github/blob/11b927189bab258a226e251c1bd87504feee51f4/tsconfig.json#L10
- Enable these rules again and fix the lint errors: https://github.com/sindresorhus/refined-github/blob/e90b58c16f58f97a0758de05ae7fe01bf7f65687/package.json#L77-L78