SONAR-6264 apply feedback

server/sonar-web/src/main/hbs/issues/facets/issues-assignee-facet.hbs

@@ -8,6 +8,8 @@
     </a>
   {{/notNull}}
 
+  <hr>
+
   {{#each values}}
     {{#eq val ''}}
     {{! unassigned }}

server/sonar-web/src/main/less/init/base.less

@@ -82,6 +82,14 @@ svg, img {
   vertical-align: top;
 }
 
+hr {
+  margin: 4px 0;
+  padding: 0;
+  height: 1px;
+  border: none;
+  background-color: @barBorderColor;
+}
+
 
 @font-face {
   font-family: 'Roboto';