DOC: Fix numpy#12959 by including negative shifts
DOC: Fix numpy#12959 by including negative shifts

Included examples symmetric to the existing ones in np.roll with negative shifts.

mhvk/numpy,abalkin/numpy,charris/numpy,shoyer/numpy,ahaldane/numpy,jorisvandenbossche/numpy,MSeifert04/numpy,WarrenWeckesser/numpy,anntzer/numpy,WarrenWeckesser/numpy,seberg/numpy,mattip/numpy,mattip/numpy,endolith/numpy,endolith/numpy,pbrod/numpy,grlee77/numpy,MSeifert04/numpy,grlee77/numpy,rgommers/numpy,shoyer/numpy,ahaldane/numpy,anntzer/numpy,seberg/numpy,madphysicist/numpy,MSeifert04/numpy,rgommers/numpy,jorisvandenbossche/numpy,mattip/numpy,mattip/numpy,WarrenWeckesser/numpy,simongibbons/numpy,MSeifert04/numpy,pbrod/numpy,mhvk/numpy,pdebuyl/numpy,ahaldane/numpy,shoyer/numpy,anntzer/numpy,pbrod/numpy,madphysicist/numpy,pizzathief/numpy,mhvk/numpy,rgommers/numpy,madphysicist/numpy,jorisvandenbossche/numpy,madphysicist/numpy,simongibbons/numpy,ahaldane/numpy,endolith/numpy,shoyer/numpy,charris/numpy,charris/numpy,seberg/numpy,pdebuyl/numpy,simongibbons/numpy,jakirkham/numpy,mhvk/numpy,abalkin/numpy,numpy/numpy,jakirkham/numpy,ahaldane/numpy,pbrod/numpy,pizzathief/numpy,MSeifert04/numpy,simongibbons/numpy,WarrenWeckesser/numpy,WarrenWeckesser/numpy,jakirkham/numpy,abalkin/numpy,seberg/numpy,pizzathief/numpy,endolith/numpy,grlee77/numpy,grlee77/numpy,numpy/numpy,anntzer/numpy,simongibbons/numpy,pdebuyl/numpy,charris/numpy,numpy/numpy,grlee77/numpy,madphysicist/numpy,shoyer/numpy,pizzathief/numpy,mhvk/numpy,jakirkham/numpy,pbrod/numpy,jorisvandenbossche/numpy,jorisvandenbossche/numpy,jakirkham/numpy,numpy/numpy,rgommers/numpy,pdebuyl/numpy,pizzathief/numpy