slightly expand tests

Author: carljm

crates/ty_python_semantic/resources/mdtest/dataclasses/dataclasses.md

@@ -110,14 +110,22 @@ reveal_type(D.__init__)  # revealed: (self: D, x: int) -> None
 ```
 
 If attributes without default values are declared after attributes with default values, a
-`TypeError` will be raised at runtime. Ideally, we would emit a diagnostic in that case:
+`TypeError` will be raised at runtime. We emit a diagnostic in that case:
 
 ```py
+from dataclasses import field
+
 @dataclass
 class D:
     x: int = 1
     # error: [dataclass-field-order] "Required field `y` cannot be defined after fields with default values"
     y: str
+
+@dataclass
+class E:
+    x: int = field(default=3)
+    # error: [dataclass-field-order]
+    y: str
 ```
 
 Pure class attributes (`ClassVar`) are not included in the signature of `__init__`: