Highlight duplicate SQL statements.

Author: jfexyz

src/DebugBar/Resources/widgets/sqlqueries/widget.css

@@ -1,4 +1,3 @@
-
 div.phpdebugbar-widgets-sqlqueries .phpdebugbar-widgets-status {
   font-family: monospace;
   padding: 6px 6px;
@@ -66,4 +65,8 @@ div.phpdebugbar-widgets-sqlqueries table.phpdebugbar-widgets-params {
 div.phpdebugbar-widgets-sqlqueries li.phpdebugbar-widgets-list-item span.phpdebugbar-widgets-error {
   display: block;
   font-weight: bold;
-}
+}
+
+div.phpdebugbar-widgets-sqlqueries li.phpdebugbar-widgets-list-item.phpdebugbar-widgets-sql-duplicate {
+  background-color: #ffc;
+}