Remove background color from KBD element

Co-authored-by: Stephen A. Bernhardt <[email protected]>

Author: westonruter

src/wp-includes/css/admin-bar.css

@@ -707,6 +707,10 @@ html:lang(he-il) .rtl #wpadminbar * {
 	content: "\f179" / '';
 }
 
+#wpadminbar #wp-admin-bar-command-palette kbd {
+	background: transparent;
+}
+
 /**
  * Customize support classes
  */