gui: Add icons to settings tabs (#5140)

Add icons to tabs in settings modal like in folder and device modal

gui/default/syncthing/device/editDeviceModalView.html

@@ -2,9 +2,9 @@
   <div class="modal-body">
     <form role="form" name="deviceEditor">
       <ul class="nav nav-tabs" ng-init="loadFormIntoScope(folderEditor)">
-        <li class="active"><a data-toggle="tab" href="#device-general"><span class="fas fa-cog"></span><span translate>General</span></a></li>
-        <li><a data-toggle="tab" href="#device-sharing"><span class="fas fa-share-alt"></span><span translate>Sharing</span></a></li>
-        <li><a data-toggle="tab" href="#device-advanced"><span class="fas fa-cogs"></span><span translate>Advanced</span></a></li>
+        <li class="active"><a data-toggle="tab" href="#device-general"><span class="fas fa-cog"></span> <span translate>General</span></a></li>
+        <li><a data-toggle="tab" href="#device-sharing"><span class="fas fa-share-alt"></span> <span translate>Sharing</span></a></li>
+        <li><a data-toggle="tab" href="#device-advanced"><span class="fas fa-cogs"></span> <span translate>Advanced</span></a></li>
       </ul>
       <div class="tab-content">
         <div id="device-general" class="tab-pane in active">

gui/default/syncthing/settings/settingsModalView.html

@@ -2,9 +2,9 @@
   <div class="modal-body">
     <form role="form" name="settingsEditor">
       <ul class="nav nav-tabs">
-        <li class="active"><a data-toggle="tab" href="#settings-general" translate>General</a></li>
-        <li><a data-toggle="tab" href="#settings-gui" translate>GUI</a></li>
-        <li><a data-toggle="tab" href="#settings-connections" translate>Connections</a></li>
+        <li class="active"><a data-toggle="tab" href="#settings-general"><span class="fas fa-cog"></span> <span translate>General</span></a></li>
+        <li><a data-toggle="tab" href="#settings-gui"><span class="fas fa-desktop"></span> <span translate>GUI</span></a></li>
+        <li><a data-toggle="tab" href="#settings-connections"><span class="fas fa-sitemap"></span> <span translate>Connections</span></a></li>
       </ul>
       <div class="tab-content">
         <div id="settings-general" class="tab-pane in active">