Merge pull request #14421 from edx/christina/wiki

Wiki accessibility fixes.

lms/static/js/wiki/CodeMirror.init.js

@@ -10,6 +10,12 @@ $(document).ready(function() {
   // Store the inital contents so we can compare for unsaved changes
     var initial_contents = editor.getValue();
 
+    // The Wiki associates a label with the text area that has ID "id_content". However, when we swap in
+    // CodeMirror, that text area is hidden. We need to associate the label with visible CodeMirror text area
+    // (and there is JS code in the wiki that depends on "id_content" interact with the content, so we have
+    // to leave that alone).
+    editor.getInputField().setAttribute('id', 'id_codemirror_content');
+    $(".control-label[for='id_content']")[0].setAttribute('for', 'id_codemirror_content');
     window.onbeforeunload = function askConfirm() { // Warn the user before they navigate away
         if (editor.getValue() != initial_contents) {
             return 'You have made changes to the article that have not been saved yet.';