ScrollableList, PlaceholderDisplayName: fix runtime warnings

app/soapbox/components/scrollable_list.js

@@ -29,7 +29,7 @@ export default class ScrollableList extends PureComponent {
     children: PropTypes.node,
     onScrollToTop: PropTypes.func,
     onScroll: PropTypes.func,
-    placeholderComponent: PropTypes.node,
+    placeholderComponent: PropTypes.func,
     placeholderCount: PropTypes.number,
   };
 

app/soapbox/features/placeholder/components/placeholder_display_name.js

@@ -21,7 +21,7 @@ export default class DisplayName extends React.Component {
             <bdi><strong className='display-name__html'>{generateText(length)}</strong></bdi>
           </span>
         </span>
-        <span class='display-name__account'>{generateText(acctLength)}</span>
+        <span className='display-name__account'>{generateText(acctLength)}</span>
       </span>
     );
   }