DOC: fix typos in contributing guide (#1862)
DOC: fix typos in contributing guide (#1862)

* DOC: fix typo in contributing section

* DOC: make minor changes in 'Updating the Doc' section

* DOC: remove whitespace

Co-authored-by: Andreas Eliasson <3c6d564542e38f43342b4987bbd20c435dd5a195@geodata.no>
jdmcbr/geopandas,jorisvandenbossche/geopandas,geopandas/geopandas,geopandas/geopandas,jorisvandenbossche/geopandas,jorisvandenbossche/geopandas,jdmcbr/geopandas,geopandas/geopandas