🩹 linalg: fix missing np.dtype type arg

Author: jorenham

scipy-stubs/linalg/_testutils.pyi

@@ -19,7 +19,7 @@ class _FakeMatrix(Generic[_ScalarT, _ShapeT]):  # undocumented
 class _FakeMatrix2(Generic[_ScalarT, _ShapeT]):  # undocumented
     _data: onp.ArrayND[_ScalarT, _ShapeT]
     def __init__(self, /, data: onp.ArrayND[_ScalarT, _ShapeT]) -> None: ...
-    def __array__(self, /, dtype: np.dtype | None = None, copy: bool | None = None) -> onp.ArrayND[_ScalarT, _ShapeT]: ...
+    def __array__(self, /, dtype: np.dtype[Any] | None = None, copy: bool | None = None) -> onp.ArrayND[_ScalarT, _ShapeT]: ...
 
 def _get_array(shape: _ShapeT, dtype: type[_ScalarT]) -> onp.ArrayND[_ScalarT, _ShapeT]: ...  # undocumented
 def _id(x: _T) -> _T: ...  # undocumented