ENH: special: Make `hyp2f1` references more specific
ENH: special: Make `hyp2f1` references more specific

Add a section number to the DLMF ref, add the citation to the
series definition in Notes, and rearrange refs in order
of appearance.

perimosocordiae/scipy,vigna/scipy,zerothi/scipy,tylerjereddy/scipy,jamestwebber/scipy,person142/scipy,jor-/scipy,tylerjereddy/scipy,jamestwebber/scipy,arokem/scipy,mdhaber/scipy,grlee77/scipy,Eric89GXL/scipy,matthew-brett/scipy,anntzer/scipy,mdhaber/scipy,scipy/scipy,matthew-brett/scipy,pizzathief/scipy,scipy/scipy,nmayorov/scipy,Stefan-Endres/scipy,aarchiba/scipy,matthew-brett/scipy,nmayorov/scipy,WarrenWeckesser/scipy,arokem/scipy,tylerjereddy/scipy,andyfaff/scipy,endolith/scipy,gertingold/scipy,pizzathief/scipy,endolith/scipy,nmayorov/scipy,pizzathief/scipy,WarrenWeckesser/scipy,anntzer/scipy,aeklant/scipy,jor-/scipy,andyfaff/scipy,aarchiba/scipy,nmayorov/scipy,gertingold/scipy,gertingold/scipy,rgommers/scipy,jor-/scipy,perimosocordiae/scipy,nmayorov/scipy,scipy/scipy,zerothi/scipy,gertingold/scipy,pizzathief/scipy,lhilt/scipy,aarchiba/scipy,e-q/scipy,rgommers/scipy,WarrenWeckesser/scipy,matthew-brett/scipy,Eric89GXL/scipy,Stefan-Endres/scipy,zerothi/scipy,lhilt/scipy,grlee77/scipy,zerothi/scipy,endolith/scipy,aeklant/scipy,rgommers/scipy,andyfaff/scipy,zerothi/scipy,Eric89GXL/scipy,mdhaber/scipy,WarrenWeckesser/scipy,Eric89GXL/scipy,e-q/scipy,jamestwebber/scipy,ilayn/scipy,tylerjereddy/scipy,Eric89GXL/scipy,anntzer/scipy,arokem/scipy,mdhaber/scipy,Stefan-Endres/scipy,andyfaff/scipy,aeklant/scipy,jamestwebber/scipy,ilayn/scipy,mdhaber/scipy,rgommers/scipy,ilayn/scipy,anntzer/scipy,scipy/scipy,vigna/scipy,jor-/scipy,vigna/scipy,aeklant/scipy,aarchiba/scipy,e-q/scipy,grlee77/scipy,lhilt/scipy,perimosocordiae/scipy,arokem/scipy,perimosocordiae/scipy,mdhaber/scipy,Stefan-Endres/scipy,Eric89GXL/scipy,jor-/scipy,e-q/scipy,lhilt/scipy,person142/scipy,andyfaff/scipy,ilayn/scipy,endolith/scipy,gertingold/scipy,vigna/scipy,zerothi/scipy,lhilt/scipy,scipy/scipy,endolith/scipy,vigna/scipy,scipy/scipy,perimosocordiae/scipy,grlee77/scipy,matthew-brett/scipy,jamestwebber/scipy,arokem/scipy,ilayn/scipy,rgommers/scipy,aarchiba/scipy,WarrenWeckesser/scipy,endolith/scipy,WarrenWeckesser/scipy,andyfaff/scipy,person142/scipy,anntzer/scipy,Stefan-Endres/scipy,Stefan-Endres/scipy,aeklant/scipy,anntzer/scipy,person142/scipy,tylerjereddy/scipy,perimosocordiae/scipy,pizzathief/scipy,grlee77/scipy,e-q/scipy,person142/scipy,ilayn/scipy