DOC: Updated linalg.pinv, .pinv2, .pinvh docstrings
DOC: Updated linalg.pinv, .pinv2, .pinvh docstrings

Included default behavior of cond parameter referencing np.finfo
See issue #4372: The docstrings now explain
the default behavior of cutting off small singular values

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