Fix up emoji not being next to autocomplete label

Fixing some preexisting issues (Safari) and some new issues (Windows
Firefox)

app/assets/stylesheets/framework/markdown_area.scss

@@ -147,6 +147,9 @@
 }
 
 .atwho-view {
+  overflow-y: auto;
+  overflow-x: hidden;
+
   small.description {
     float: right;
     padding: 3px 5px;
@@ -162,4 +165,8 @@
       @include disableAllAnimation;
     }
   }
+
+  ul > li {
+    white-space: nowrap;
+  }
 }