layouts: remove unnecessary li closing tags

Author: davvid

_layouts/headerbar.html

@@ -17,12 +17,12 @@
             <span class="headerbar-text">The highly caffeinated Git GUI</span>
         </div>
         <nav class="headerbar-nav">
-            <a href="downloads.html">Download</a></li>
-            <a href="share/doc/git-cola/hotkeys.html">Keyboard Shortcuts</a></li>
-            <a href="https://git-cola.readthedocs.io/en/latest/">Documentation</a></li>
-            <a href="screenshots.html">Screenshots</a></li>
-            <a href="https://github.com/git-cola/git-cola">Source</a></li>
-            <a href="about.html">About</a></li>
+            <a href="downloads.html">Download</a>
+            <a href="share/doc/git-cola/hotkeys.html">Keyboard Shortcuts</a>
+            <a href="https://git-cola.readthedocs.io/en/latest/">Documentation</a>
+            <a href="screenshots.html">Screenshots</a>
+            <a href="https://github.com/git-cola/git-cola">Source</a>
+            <a href="about.html">About</a>
         </nav>
     </header>