Update scala3doc/resources/dotty_res/styles/diagram.css

Co-authored-by: Guillaume Raffin <theelectronwill@gmail.com>

Author: abgruszecki

scala3doc/resources/dotty_res/styles/diagram.css

@@ -23,7 +23,9 @@
   text-decoration: underline;
   color: #FFF;
 }
-
+.diagram-class a:hover {
+  color: #BFE7F3;
+}
 .diagram-class span[data-unresolved-link] {
   color: #FFF;
-}
+}