Add profile directory link to single column navigation panel (mastodon#10963)

Author: Gargron

app/javascript/mastodon/features/ui/components/navigation_panel.js

@@ -22,7 +22,8 @@ const NavigationPanel = () => (
     <hr />
 
     <a className='column-link column-link--transparent' href='/settings/preferences'><Icon className='column-link__icon' id='cog' fixedWidth /><FormattedMessage id='navigation_bar.preferences' defaultMessage='Preferences' /></a>
-    <a className='column-link column-link--transparent' href='/relationships'><Icon className='column-link__icon' id='address-book-o' fixedWidth /><FormattedMessage id='navigation_bar.follows_and_followers' defaultMessage='Follows and followers' /></a>
+    <a className='column-link column-link--transparent' href='/relationships'><Icon className='column-link__icon' id='users' fixedWidth /><FormattedMessage id='navigation_bar.follows_and_followers' defaultMessage='Follows and followers' /></a>
+    <a className='column-link column-link--transparent' href='/explore'><Icon className='column-link__icon' id='address-book-o' fixedWidth /><FormattedMessage id='navigation_bar.profile_directory' defaultMessage='Profile directory' /></a>
   </div>
 );