Add forgotten release notes to web site

Author: marijnh

doc/releases.html

@@ -30,6 +30,18 @@ <h2>Release notes and version history</h2>
 
   <h2>Version 5.x</h2>
 
+  <p class="rel">20-06-2016: <a href="http://codemirror.net/codemirror-5.16.0.zip">Version 5.16.0</a>:</p>
+
+  <ul class="rel-note">
+    <li>Fix glitches when dragging content caused by the drop indicator receiving mouse events.</li>
+    <li>Make Control-drag work on Firefox.</li>
+    <li>Make clicking or selection-dragging at the end of a wrapped line select the right position.</li>
+    <li><a href="http://codemirror.net/doc/manual.html#addon_show-hint">show-hint addon</a>: Prevent widget scrollbar from hiding part of the hint text.</li>
+    <li><a href="http://codemirror.net/doc/manual.html#addon_rulers">rulers addon</a>: Prevent rulers from forcing a horizontal editor scrollbar.</li>
+    <li><a href="http://codemirror.net/doc/manual.html#addon_search">search addon</a>: Automatically bind search-related keys in persistent dialog.</li>
+    <li><a href="http://codemirror.net/demo/sublime.html">sublime keymap</a>: Add a multi-cursor aware smart backspace binding.</li>
+  </ul>
+
   <p class="rel">20-05-2016: <a href="http://codemirror.net/codemirror-5.15.2.zip">Version 5.15.2</a>:</p>
 
   <ul class="rel-note">