Update eslint and its plugins, enable more rules and fix their findings:
1. `unicorn/no-unsafe-string-replacement` found that uploading a file
whose name contains `$&` inserted a broken markdown link, because
`String#replace` expands such patterns in the replacement string
2. `@typescript-eslint/require-await` removes `async` from functions
that never await
3. Plugin rules not covered by a preset are now listed explicitly
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Co-authored-by: bircni <bircni@icloud.com>
None of the frontend js/ts files was touched besides these two commands
(edit: no longer true, I touched one file in
https://github.com/go-gitea/gitea/pull/31559/commits/61105d0618e285d97e95044bfb64415f364a4526
because of a deprecation that was not showing before the rename).
`tsc` currently reports 778 errors, so I have disabled it in CI as
planned.
Everything appears to work fine.