Document notification filters. #2231

src/General/Settings/Filter-guide.html

@@ -30,6 +30,10 @@
     Highlighted OPs will have their threads put on top of the board index by default.<br>
     For example: <code>top:yes;</code> or <code>top:no;</code>.
   </li>
+  <li>
+    Show a desktop notification instead of hiding.<br>
+    For example: <code>notify;</code>.
+  </li>
   <li>
     Filters in the "General" section apply to multiple fields, by default <code>subject,name,filename,comment</code>.<br>
     The fields can be specified with the <code>type</code> option, separated by commas.<br>