Bug 1523774 - Hide the secondary separator em dash when the title is empty. r=dao

Seems like we want to hide it whenever the title is empty, not only in the search @alias case that this bug was filed about.

Differential Revision: https://phabricator.services.mozilla.com/D18004

--HG--
extra : moz-landing-system : lando

browser/themes/shared/urlbar-autocomplete.inc.css

@@ -106,6 +106,10 @@
   margin: 0 .4em;
 }
 
+.urlbarView-title:empty + .urlbarView-secondary::before {
+  display: none;
+}
+
 .urlbarView-secondary {
   color: var(--urlbar-popup-action-color);
   font-size: 0.9em;