Add 'Object' built-in type

test/highlight/built-ins.tig

@@ -13,10 +13,17 @@ let
 
   var c : int := "This is an \"int\""
   /*      ^ type.builtin (not sure why it isn't 'type')*/
+
+  var d : Object := nil
+  /*      ^ type.builtin */
+
+  type Object = int
 in
   let
     var c : int := "This is an int"
     /*      ^ type.builtin (not sure why it isn't 'type')*/
+    var d : Object := "This is an object"
+    /*      ^ type.builtin (not sure why it isn't 'type')*/
   in
   end;
 

test/highlight/object-oriented.tig

@@ -2,7 +2,7 @@ let
   class A extends Object {}
   /* <- keyword */
   /*      ^ keyword */
-  /*              ^ type */
+  /*              ^ type.builtin */
 
   type B = class extends A {
   /*       ^ keyword */