Use const instead of let for constant (#6106)

app/javascript/mastodon/features/getting_started/index.js

@@ -48,7 +48,7 @@ export default class GettingStarted extends ImmutablePureComponent {
   render () {
     const { intl, myAccount, columns, multiColumn } = this.props;
 
-    let navItems = [];
+    const navItems = [];
 
     if (multiColumn) {
       if (!columns.find(item => item.get('id') === 'HOME')) {
@@ -68,20 +68,20 @@ export default class GettingStarted extends ImmutablePureComponent {
       }
     }
 
-    navItems = navItems.concat([
+    navItems.push(
       <ColumnLink key='4' icon='star' text={intl.formatMessage(messages.favourites)} to='/favourites' />,
       <ColumnLink key='5' icon='thumb-tack' text={intl.formatMessage(messages.pins)} to='/pinned' />,
-      <ColumnLink key='6' icon='bars' text={intl.formatMessage(messages.lists)} to='/lists' />,
-    ]);
+      <ColumnLink key='6' icon='bars' text={intl.formatMessage(messages.lists)} to='/lists' />
+    );
 
     if (myAccount.get('locked')) {
       navItems.push(<ColumnLink key='7' icon='users' text={intl.formatMessage(messages.follow_requests)} to='/follow_requests' />);
     }
 
-    navItems = navItems.concat([
+    navItems.push(
       <ColumnLink key='8' icon='volume-off' text={intl.formatMessage(messages.mutes)} to='/mutes' />,
-      <ColumnLink key='9' icon='ban' text={intl.formatMessage(messages.blocks)} to='/blocks' />,
-    ]);
+      <ColumnLink key='9' icon='ban' text={intl.formatMessage(messages.blocks)} to='/blocks' />
+    );
 
     if (multiColumn) {
       navItems.push(<ColumnLink key='10' icon='question' text={intl.formatMessage(messages.keyboard_shortcuts)} to='/keyboard-shortcuts' />);