Add hints for rules (#29539)

app/javascript/mastodon/features/about/index.jsx

@@ -170,7 +170,8 @@ class About extends PureComponent {
               <ol className='rules-list'>
                 {server.get('rules').map(rule => (
                   <li key={rule.get('id')}>
-                    <span className='rules-list__text'>{rule.get('text')}</span>
+                    <div className='rules-list__text'>{rule.get('text')}</div>
+                    {rule.get('hint').length > 0 && (<div className='rules-list__hint'>{rule.get('hint')}</div>)}
                   </li>
                 ))}
               </ol>

app/javascript/styles/mastodon/about.scss

@@ -53,4 +53,10 @@ $fluid-breakpoint: $maximum-width + 20px;
       border-bottom: 0;
     }
   }
+
+  &__hint {
+    font-size: 14px;
+    font-weight: 400;
+    color: $darker-text-color;
+  }
 }