Expand NamedExpr range to include full range of parenthesized value (#6632)

## Summary

Given:

```python
if (
    x
    :=
    (  # 4
        y # 5
    )  # 6
):
    pass
```

It turns out the parser ended the range of the `NamedExpr` at the end of
`y`, rather than the end of the parenthesis that encloses `y`. This just
seems like a bug -- the range should be from the start of the name on
the left, to the end of the parenthesized node on the right.

## Test Plan

`cargo test`

crates/ruff_python_parser/src/parser.rs

@@ -603,6 +603,13 @@ def func[T, U: str, *Ts, **P]():
         insta::assert_debug_snapshot!(parse_ast);
     }
 
+    #[test]
+    fn test_named_expression() {
+        let source = "(x := ( y * z ))";
+        let parse_ast = parse_expression(source, "<test>").unwrap();
+        insta::assert_debug_snapshot!(parse_ast);
+    }
+
     #[test]
     fn test_with_statement() {
         let source = "\

crates/ruff_python_parser/src/python.lalrpop

@@ -1335,15 +1335,19 @@ NamedExpressionTest: ast::Expr = {
     Test<"all">,
 }
 
+NamedExpressionName: ast::Expr = {
+    <location:@L> <id:Identifier> <end_location:@R> => ast::Expr::Name(
+        ast::ExprName { id: id.into(), ctx: ast::ExprContext::Store, range: (location..end_location).into() },
+    ),
+}
+
 NamedExpression: ast::Expr = {
-    <location:@L> <id:Identifier> <end_location:@R> ":=" <value:Test<"all">> => {
+    <location:@L> <target:NamedExpressionName> ":=" <value:Test<"all">> <end_location:@R> => {
         ast::Expr::NamedExpr(
             ast::ExprNamedExpr {
-                target: Box::new(ast::Expr::Name(
-                    ast::ExprName { id: id.into(), ctx: ast::ExprContext::Store, range: (location..end_location).into() },
-                )),
-                range: (location..value.end()).into(),
+                target: Box::new(target),
                 value: Box::new(value),
+                range: (location..end_location).into(),
             }
         )
     },

crates/ruff_python_parser/src/snapshots/ruff_python_parser__parser__tests__named_expression.snap

@@ -0,0 +1,36 @@
+---
+source: crates/ruff_python_parser/src/parser.rs
+expression: parse_ast
+---
+NamedExpr(
+    ExprNamedExpr {
+        range: 1..15,
+        target: Name(
+            ExprName {
+                range: 1..2,
+                id: "x",
+                ctx: Store,
+            },
+        ),
+        value: BinOp(
+            ExprBinOp {
+                range: 8..13,
+                left: Name(
+                    ExprName {
+                        range: 8..9,
+                        id: "y",
+                        ctx: Load,
+                    },
+                ),
+                op: Mult,
+                right: Name(
+                    ExprName {
+                        range: 12..13,
+                        id: "z",
+                        ctx: Load,
+                    },
+                ),
+            },
+        ),
+    },
+)