### Pandas version checks - [X] I have checked that the issue still exists on the latest versions of the docs on `main` [here](https://pandas.pydata.org/docs/dev/) ### Location of the documentation https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.api.types.is_period_dtype.html#pandas.api.types.is_period_dtype ### Documentation problem Suggests the user use `isinstance(dtype, pd.Period)` instead, when they really need to use `Use isinstance(dtype, pd.PeriodDtype)` ### Suggested fix for documentation Update message to reference correct class