Add new JS linter rules (#17699)

* Add new JS linter rules

Adds a few useful rules from eslint-plugin-github. Notable changes:

- Forbid dataset usage, its camel-casing behaviour makes it hard to
  grep for attributes.
- Forbid .then() and .catch(), we should generally prefer await for new
  code. For rare cases where they are useful, a eslint-disable-line
  directive can be set.
- Add docs js to linting

* also enable github/array-foreach

* small tweak

Co-authored-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

web_src/js/features/repo-legacy.js

@@ -162,7 +162,7 @@ export function initRepoCommentForm() {
           'clear',
           $listMenu.data('issue-id'),
           '',
-        ).then(() => window.location.reload());
+        ).then(() => window.location.reload()); // eslint-disable-line github/no-then
       }
 
       $(this).parent().find('.item').each(function () {
@@ -205,7 +205,7 @@ export function initRepoCommentForm() {
           '',
           $menu.data('issue-id'),
           $(this).data('id'),
-        ).then(() => window.location.reload());
+        ).then(() => window.location.reload()); // eslint-disable-line github/no-then
       }
 
       let icon = '';
@@ -238,7 +238,7 @@ export function initRepoCommentForm() {
           '',
           $menu.data('issue-id'),
           $(this).data('id'),
-        ).then(() => window.location.reload());
+        ).then(() => window.location.reload()); // eslint-disable-line github/no-then
       }
 
       $list.find('.selected').html('');