Pandas version checks

• I have checked that the issue still exists on the latest versions of the docs on main here

Location of the documentation

None: It's not there!

Documentation problem

pandas.api.types.is_dtype_equal() is not documented, but it is used in tests/extension/decimal/array.py which is used as an example ExtensionArray implementation

Suggested fix for documentation

Unsure if we want this in the public API or not, but if so, we ought to fix it.

See pandas-dev/pandas-stubs#1112 for some discussion