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/markup/tasklist.js

@@ -14,14 +14,14 @@ export function initMarkupTasklist() {
     const checkboxes = el.querySelectorAll(`.task-list-item input[type=checkbox]`);
 
     for (const checkbox of checkboxes) {
-      if (checkbox.dataset.editable) {
+      if (checkbox.hasAttribute('data-editable')) {
         return;
       }
 
-      checkbox.dataset.editable = 'true';
+      checkbox.setAttribute('data-editable', 'true');
       checkbox.addEventListener('input', async () => {
         const checkboxCharacter = checkbox.checked ? 'x' : ' ';
-        const position = parseInt(checkbox.dataset.sourcePosition) + 1;
+        const position = parseInt(checkbox.getAttribute('data-source-position')) + 1;
 
         const rawContent = container.querySelector('.raw-content');
         const oldContent = rawContent.textContent;
@@ -43,7 +43,8 @@ export function initMarkupTasklist() {
 
         try {
           const editContentZone = container.querySelector('.edit-content-zone');
-          const {updateUrl, context} = editContentZone.dataset;
+          const updateUrl = editContentZone.getAttribute('data-update-url');
+          const context = editContentZone.getAttribute('data-context');
 
           await $.post(updateUrl, {
             ignore_attachments: true,