Improve a11y by adding empty alt to middle dot

app/assets/stylesheets/framework/mixins.scss

@@ -404,7 +404,10 @@
 
 @mixin middle-dot-divider {
   &::after {
-    content: '\00B7'; // Middle Dot
+    // Duplicate `content` property used as a fallback
+    // scss-lint:disable DuplicateProperty
+    content: '\00B7'; // middle dot fallback if browser does not support alternative content
+    content: '\00B7' / ''; // tell screen readers to ignore the content https://www.w3.org/TR/css-content-3/#accessibility
     padding: 0 6px;
     font-weight: $gl-font-weight-bold;
   }