Remove empty li element from release notes (#10326)

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

@@ -126,7 +126,6 @@
         <li><tt>AbstractDateField</tt> is not a <tt>LegacyComponent</tt> anymore.</li>
         <li><tt>AbstractDateField</tt>.<tt>formatDate</tt> is now abstract.</li>
         <li><tt>VAbstractTextualDate</tt>.<tt>updateDateVariables()</tt> is now <tt>updateBufferedResolutions()</tt> and <tt>updateAndSendBufferedValues()</tt>.</li>
-        <li><tt></tt></li>
         <li>For <tt>GridDragStartEvent</tt> and <tt>GridDragEndEvent</tt> classes, the method <tt>getDraggedItems</tt> now returns a <tt>List</tt> instead of a <tt>Set</tt>, with the first-to-last item ordering from client side.</li>
 
         <h2>For incompatible or behavior-altering changes in 8.1, please see <a href="https://vaadin.com/download/release/8.1/8.1.0/release-notes.html#incompatible">8.1 release notes</a></h2>