Fix hardcoded strings (#2997)

htdocs/interaction/forum/lang/en.utf8/interaction.forum.php

@@ -64,6 +64,7 @@ $string['editstothispost'] = 'Edits to this post:';
 $string['edittitle'] = 'Edit forum';
 $string['edittopic'] = 'Edit topic';
 $string['edittopicsuccess'] = 'Topic edited successfully';
+$string['forumname'] = 'Forum Name';
 $string['forumsuccessfulsubscribe'] = 'Forum subscribed successfully';
 $string['forumsuccessfulunsubscribe'] = 'Forum unsubscribed successfully';
 $string['gotoforums'] = 'Go to forums';

htdocs/interaction/forum/theme/default/index.tpl

@@ -18,9 +18,9 @@
 {if $forums}
 <table id="forumslist">
 	<tr>
-		<th>Forum Name</th>
-		<th>Description</th>
-		<th>Topics</th>
+		<th>{str tag="forumname" section="interaction.forum"}</th>
+		<th>{str tag="description"}</th>
+		<th>{str tag="Topics" section="interaction.forum"}</th>
 		<th></th>
 		<th></th>
 	</tr>