text: Title: TYP: `timedelta64.__divmod__` incorrect inference
  Body: ### Describe the issue:
  
  Using `divmod` widens generic type of timedelta64. The last overload should probably use `Self` instead of `timedelta64`, or possible add an overload for the timedelta case.
  
  https://github.com/numpy/numpy/blob/6bc905859780c44193942ea2d0d297abcd691330/numpy/__init__.pyi#L4472-L4477
  
  
  ### Reproduce the code example:
  
  ```python
  from datetime import timedelta as TD
  from typing import assert_type
  
  import numpy as np
  
  td = np.timedelta64(1, "D")
  assert_type(td, np.timedelta64[TD])  # ✅
  
  n, remainder = divmod(td, td)
  assert_type(remainder, np.timedelta64[TD])  # ❌ timedelta64[timedelta | int | None]
  ```
  
  ### Python and NumPy Versions:
  
  2.2.2
  3.13.1 (main, Dec  4 2024, 08:54:14) [GCC 11.4.0]
  
  ### Type-checker version and settings:
  
  mypy 1.4.1
  pyright 1.1.393