Adjust the scheme option docs to reflect the source code (#693)
Adjust the scheme option docs to reflect the source code (#693)

I noticed some differences between the docs and the source code. By default scheme is ``None`` and ``equal_interval`` mustn't end with an s otherwise an exception is raised. I also changed the link because the current URL resolves to a 404 error.
geopandas/geopandas,ozak/geopandas,geopandas/geopandas,jorisvandenbossche/geopandas,jorisvandenbossche/geopandas,jdmcbr/geopandas,ozak/geopandas,geopandas/geopandas,jdmcbr/geopandas,jorisvandenbossche/geopandas