Add ref to docstring of Series:dtype
- [x] closes #24325 
- [ ] tests added / passed
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
Add ``:ref:`basics.dtypes` `` to the docstring of `dtype` of `pandas.Series`. 

@TomAugspurger Should we also add your examples to `basics.dtypes` ? 
```python
pd.Series([1, 2], dype=np.dtype("int64"))
pd.Series([1, 2], dtype=pd.api.types.CategoricalDtype([1, 2, 3]))
```