fix(a11y): convert empty links to buttons (#3926)

extensions/tags/js/src/forum/addTagComposer.js

@@ -2,6 +2,7 @@ import app from 'flarum/forum/app';
 import { extend, override } from 'flarum/common/extend';
 import IndexSidebar from 'flarum/forum/components/IndexSidebar';
 import classList from 'flarum/common/utils/classList';
+import Button from 'flarum/common/components/Button';
 
 import tagsLabel from '../common/helpers/tagsLabel';
 import getSelectableTags from './utils/getSelectableTags';
@@ -47,13 +48,16 @@ export default function addTagComposer() {
 
     items.add(
       'tags',
-      <a className={classList(['DiscussionComposer-changeTags', !selectableTags.length && 'disabled'])} onclick={this.chooseTags.bind(this)}>
+      <Button
+        className={classList(['DiscussionComposer-changeTags', 'Button Button--ua-reset', !selectableTags.length && 'disabled'])}
+        onclick={this.chooseTags.bind(this)}
+      >
         {tags.length ? (
           tagsLabel(tags)
         ) : (
           <span className="TagLabel untagged">{app.translator.trans('flarum-tags.forum.composer_discussion.choose_tags_link')}</span>
         )}
-      </a>,
+      </Button>,
       10
     );
   });

extensions/tags/less/forum.less

@@ -32,6 +32,7 @@
 }
 .DiscussionComposer-changeTags {
   margin-right: 15px;
+  line-height: inherit;
 
   &.disabled {
     opacity: 0.5;