DOC: Add remarks about array vs scalar output to every ufunc
DOC: Add remarks about array vs scalar output to every ufunc

Some ufuncs already mentioned this, but it seems sensible for all of them to describe it in exactly the same way.

anntzer/numpy,charris/numpy,seberg/numpy,simongibbons/numpy,abalkin/numpy,ahaldane/numpy,pizzathief/numpy,mhvk/numpy,pdebuyl/numpy,simongibbons/numpy,abalkin/numpy,mhvk/numpy,mattip/numpy,madphysicist/numpy,endolith/numpy,jorisvandenbossche/numpy,pdebuyl/numpy,jorisvandenbossche/numpy,pdebuyl/numpy,pbrod/numpy,pbrod/numpy,tynn/numpy,numpy/numpy,jakirkham/numpy,shoyer/numpy,endolith/numpy,gfyoung/numpy,jorisvandenbossche/numpy,madphysicist/numpy,grlee77/numpy,mhvk/numpy,mhvk/numpy,rgommers/numpy,WarrenWeckesser/numpy,mattip/numpy,jakirkham/numpy,simongibbons/numpy,seberg/numpy,gfyoung/numpy,endolith/numpy,pbrod/numpy,MSeifert04/numpy,rgommers/numpy,WarrenWeckesser/numpy,simongibbons/numpy,shoyer/numpy,mattip/numpy,charris/numpy,Eric89GXL/numpy,endolith/numpy,pizzathief/numpy,anntzer/numpy,grlee77/numpy,charris/numpy,ahaldane/numpy,numpy/numpy,seberg/numpy,shoyer/numpy,grlee77/numpy,anntzer/numpy,jakirkham/numpy,ahaldane/numpy,pbrod/numpy,WarrenWeckesser/numpy,pizzathief/numpy,Eric89GXL/numpy,madphysicist/numpy,ahaldane/numpy,madphysicist/numpy,pbrod/numpy,jakirkham/numpy,pdebuyl/numpy,mattip/numpy,ahaldane/numpy,pizzathief/numpy,WarrenWeckesser/numpy,MSeifert04/numpy,simongibbons/numpy,Eric89GXL/numpy,jorisvandenbossche/numpy,rgommers/numpy,numpy/numpy,anntzer/numpy,gfyoung/numpy,grlee77/numpy,tynn/numpy,WarrenWeckesser/numpy,MSeifert04/numpy,shoyer/numpy,madphysicist/numpy,rgommers/numpy,Eric89GXL/numpy,MSeifert04/numpy,charris/numpy,numpy/numpy,MSeifert04/numpy,tynn/numpy,pizzathief/numpy,grlee77/numpy,jakirkham/numpy,jorisvandenbossche/numpy,seberg/numpy,shoyer/numpy,abalkin/numpy,mhvk/numpy