Improve error messaging for reserved keywords (bug 6199).

sourcepawn/compiler/tests/fail-object-keyword-as-name.sp

@@ -0,0 +1,5 @@
+public Action:SomeEvent( Handle:event, const String:name[], bool:dontBroadcast)
+{
+    // error 143: new-style declarations should not have "new"
+    new object = GetEventInt(event, "object");
+}

sourcepawn/compiler/tests/fail-object-keyword-as-name.txt

@@ -0,0 +1 @@
+(4) : error 157: 'object' is a reserved keyword