add missing tooltip for dashboard link (fix #837)

src/popup.html

@@ -19,7 +19,7 @@
 </div>
 
 <div class="paneHead">
-    <a id="gotoDashboard" class="extensionURL" href="#" data-extension-url="dashboard.html">uMatrix <span id="version"> </span><span class="fa">&#xf013;</span></a>
+    <a id="gotoDashboard" class="extensionURL" href="#" data-extension-url="dashboard.html" data-i18n-tip="matrixDashboardMenuEntry">uMatrix <span id="version"> </span><span class="fa">&#xf013;</span></a>
     <div id="toolbarContainer">
         <div class="toolbar">
             <span class="scope" id="specificScope"><span>&nbsp;</span></span><!--