Rename subject col in content tables

Author: khemarato

_includes/big_content_table.html

@@ -9,7 +9,7 @@
     <th>Formats</th>
     <th>Year</th>
     <th>Author(s)</th>
-    <th>Featured In...</th>
+    <th>Subject</th>
     <th>Date Added</th>
     <th>Size</th>
     <th><i class="fas fa-cloud-arrow-down"></i><span style="display: none">Downloads</span></th>{% if include.publishercol %}