Fix upvalues.lua comment
@@ -21,7 +21,9 @@ local analyze_upvalues
--
-- _upvalues:
-- In Program node
--- List of Toplevel AST value nodes (Var, Func and Record).
+-- List of Upvalue.T:
+-- - string literals
+-- - Toplevel AST value nodes (Var, Func and Record).
--
-- _literals:
-- In Program node
