Make hit area bigger on settings ‘change’ links

Bigger hit areas are generally better (cf Fitt’s law[1]), as long as
they’re not ambiguous.

This commit enlarges the hit area of the edit links (using a border) so
they fill the same vertical space as the smallest possible row (going
to the full height might look weird because some of these rows get very
tall).

app/assets/stylesheets/components/table.scss

@@ -212,8 +212,23 @@
 }
 
 .table-field-right-aligned {
+
   @extend %table-field;
   text-align: right;
+
+  a {
+
+    display: block;
+    border-top: 11px solid transparent;
+    border-bottom: 8px solid transparent;
+    margin: -11px 0 -8px 0;
+
+    &:hover {
+      color: $link-hover-colour;
+    }
+
+  }
+
 }