update cheatsheet

flaskbb/templates/editor_help.html

@@ -10,7 +10,7 @@
                 <div class="cheatsheet">
                     <h2>Emojis</h2>
                     <div class="emojis">
-                        A full list of available emojis can be found <a href="http://www.emoji-cheat-sheet.com/">here</a>.
+                        To enter emoji, type a colon and let the editor autocomplete the emoji short name for you. A full list of available emoji can be found <a href="https://unicode.org/emoji/charts/full-emoji-list.html">here</a>.
                     </div>
 
                     <h2>Typography</h2>