[Glitch] Change at icon in notification filter to reply-all

Port cfe2d1cc4a to glitch-soc

Signed-off-by: Thibaut Girka <thib@sitedethib.com>

app/javascript/flavours/glitch/features/notifications/components/filter_bar.js

@@ -64,7 +64,7 @@ class FilterBar extends React.PureComponent {
           onClick={this.onClick('mention')}
           title={intl.formatMessage(tooltips.mentions)}
         >
-          <Icon id='at' fixedWidth />
+          <Icon id='reply-all' fixedWidth />
         </button>
         <button
           className={selectedFilter === 'favourite' ? 'active' : ''}