DOC: interpolate:  improve RectBivariateSpline doc
DOC: interpolate:  improve RectBivariateSpline doc

ilayn/scipy,endolith/scipy,anntzer/scipy,Stefan-Endres/scipy,perimosocordiae/scipy,WarrenWeckesser/scipy,rgommers/scipy,anntzer/scipy,vigna/scipy,endolith/scipy,andyfaff/scipy,mdhaber/scipy,WarrenWeckesser/scipy,ilayn/scipy,mdhaber/scipy,endolith/scipy,mdhaber/scipy,Stefan-Endres/scipy,anntzer/scipy,scipy/scipy,anntzer/scipy,scipy/scipy,zerothi/scipy,Stefan-Endres/scipy,andyfaff/scipy,perimosocordiae/scipy,Stefan-Endres/scipy,mdhaber/scipy,anntzer/scipy,WarrenWeckesser/scipy,ilayn/scipy,zerothi/scipy,vigna/scipy,Stefan-Endres/scipy,endolith/scipy,endolith/scipy,rgommers/scipy,vigna/scipy,scipy/scipy,zerothi/scipy,WarrenWeckesser/scipy,mdhaber/scipy,perimosocordiae/scipy,perimosocordiae/scipy,anntzer/scipy,scipy/scipy,Stefan-Endres/scipy,rgommers/scipy,endolith/scipy,ilayn/scipy,vigna/scipy,ilayn/scipy,perimosocordiae/scipy,zerothi/scipy,mdhaber/scipy,zerothi/scipy,ilayn/scipy,scipy/scipy,andyfaff/scipy,scipy/scipy,andyfaff/scipy,WarrenWeckesser/scipy,vigna/scipy,rgommers/scipy,rgommers/scipy,WarrenWeckesser/scipy,zerothi/scipy,perimosocordiae/scipy,andyfaff/scipy,andyfaff/scipy