ENH: add docstring of butter() for transfer function syntax problem (#11404)
ENH: add docstring of butter() for transfer function syntax problem (#11404)

* add docstring for transfer function syntax problem

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