Core: Add defer

core_printer.cpp

@@ -243,6 +243,12 @@ void core__stringify(Ast *ast) {
             core__stringify(n->expr);
         } break;
 
+        case AST_DEFER: {
+            auto n = (Ast_Defer *)ast;
+            genln("defer");
+            core__stringify(n->scope);
+        } break;
+
         case AST_PASS: {
             genln("pass");
         } break;