Add Decorator node (#7)

parser/src/parser.rs

@@ -1102,7 +1102,7 @@ def args_to_tuple(*args: *Ts) -> Tuple[*Ts]: ...
     }
 
     #[test]
-    #[cfg(not(feature = "all-nodes-with-ranges"))]
+    #[cfg(feature = "all-nodes-with-ranges")]
     fn decorator_ranges() {
         let parse_ast = parse_program(
             r#"

parser/src/python.lalrpop

@@ -1151,9 +1151,9 @@ ClassDef: ast::Stmt = {
 };
 
 // Decorators:
-Decorator: ast::Expr = {
-    <location:@L> "@" <p:NamedExpressionTest> "\n" => {
-        p
+Decorator: ast::Decorator = {
+    <location:@L> "@" <p:NamedExpressionTest> <end_location:@R> "\n" => {
+        ast::Decorator { range: optional_range(location, end_location), expression: p }
     },
 };