Add spaces where needed.

preferences/templates/preferences/display_preferences.html

@@ -210,7 +210,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 <div  class="panel panel-default" id="switches">
     <div class="panel-heading" data-toggle="collapse" href="#collapse_switches">
         <h4 class="panel-title">
-            <a><i class="fa fa-server"></i>{% trans "Configuration of switches" %}</a>
+            <a><i class="fa fa-server"></i> {% trans "Configuration of switches" %}</a>
         </h4>
     </div>
     <div id="collapse_switches" class="panel-collapse panel-body collapse">
@@ -387,7 +387,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 <div  class="panel panel-default" id="mail">
     <div class="panel-heading" data-toggle="collapse" href="#collapse_mail">
         <h4 class="panel-title">
-                <a><i class="fa fa-comment"></i>{% trans "Message for emails" %}</a>
+                <a><i class="fa fa-comment"></i> {% trans "Message for emails" %}</a>
         </h4>
     </div>
     <div id="collapse_mail" class="panel-collapse panel-body collapse">
@@ -414,7 +414,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 <div  class="panel panel-default" id="rappels">
     <div class="panel-heading" data-toggle="collapse" href="#collapse_rappels">
         <h4 class="panel-title">
-                <a><i class="fa fa-bell"></i>{% trans "Options for the membership's end email" %}</a>
+                <a><i class="fa fa-bell"></i> {% trans "Options for the membership's end email" %}</a>
         </h4>
     </div>
     <div id="collapse_rappels" class="panel-collapse panel-body collapse">
@@ -465,7 +465,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 <div class="panel panel-default" id="social">
     <div class="panel-heading" data-toggle="collapse" href="#collapse_social">
         <h4 class="panel-title">
-                <a><i class="fa fa-facebook"></i><i class="fa fa-twitter"></i>{% trans "Social networks" %}</a>
+                <i class="fa fa-twitter"></i> {% trans "Social networks" %}</a>
         </h4>
     </div>
     <div id="collapse_social" class="panel-collapse panel-body collapse">