Add list of possible projections to GeoSeries.map()

[khider]

Is your feature request related to a problem? Please describe.
This is more of a PaleoPAL problem, although it would help other users to know what projections are available to them.

Describe the solution you'd like
Just add a list of possible projections to the docstrings of the mapping functions (GeoSeries and MultipleGeoSeries).