Add mention of ContextMenu changes to Release Notes (#11085)

all/src/main/templates/release-notes.html

@@ -83,7 +83,8 @@ <h2 id="enhancements">Enhancements in Vaadin Framework @version-minor@</h2>
             enhancements. Below is a list of the most notable changes:</p>
 
         <ul>
-
+            <li>Improvements in <tt>MenuBar</tt> client-side customization.</tt>
+            <li>Support for improved version of <tt>ContextMenu</tt> add-on.</li>
         </ul>
 
         </p>
@@ -99,6 +100,7 @@ <h2 id="enhancements">Enhancements in Vaadin Framework @version-minor@</h2>
         <h2 id="incompatible">Incompatible or Behavior-altering Changes in @version-minor@</h2>
 
         <ul>
+            <li><tt>VOverlay</tt> workaround with <tt>static</tt> reference to current overlay has been removed</tt>
         </ul>
 
         <h2>For incompatible or behavior-altering changes in 8.5, please see <a href="https://vaadin.com/download/release/8.5/8.5.0/release-notes.html#incompatible">8.5 release notes</a></h2>