improve diagnostics in call parsing, patch suggested by
Matthijs Kooijman

llvm-svn: 49648
diff --git a/llvm/docs/tutorial/LangImpl6.html b/llvm/docs/tutorial/LangImpl6.html
index 1f159e0..6059ad0e 100644
--- a/llvm/docs/tutorial/LangImpl6.html
+++ b/llvm/docs/tutorial/LangImpl6.html
@@ -1085,7 +1085,7 @@
       if (CurTok == ')') break;
       
       if (CurTok != ',')
-        return Error("Expected ')'");
+        return Error("Expected ')' or ',' in argument list");
       getNextToken();
     }
   }