Second round of cleanups for new optional parameter semantics.

pkg/dartdoc/lib/src/mirrors/dart2js_mirror.dart

Index: pkg/dartdoc/lib/src/mirrors/dart2js_mirror.dart
===================================================================
--- pkg/dartdoc/lib/src/mirrors/dart2js_mirror.dart	(revision 13754)
+++ pkg/dartdoc/lib/src/mirrors/dart2js_mirror.dart	(working copy)
@@ -171,8 +171,8 @@
   }
 
   void internalError(String message,
-                     [Node node, Token token, HInstruction instruction,
-                      Element element]) {
+                     {Node node, Token token, HInstruction instruction,
+                      Element element}) {
     cancel('Internal error: $message', node, token, instruction, element);
   }