Add a little note about emoticon filters

www/channel.html

@@ -244,6 +244,7 @@
         </div>
         <div class="row modonly" id="filtereditor" style="display: none;">
             <div class="span12">
+                <p><strong>Note:</strong> if you just want simple word replacement, like emoticons, put the word in the Regex field, use <code>ig</code> for the flags, and put the replacement in the Replacement field.</p>
                 <table class="table table-striped">
                     <thead>
                         <th></th>