DOC: add a "Returns" section for `np.frombuffer`
DOC: add a "Returns" section for `np.frombuffer`

This is a pre-requisite for Issue#16751. See comments on PR#18964
starting at github.com/numpy/numpy/pull/18964#issuecomment-847492524

simongibbons/numpy,seberg/numpy,mattip/numpy,mattip/numpy,anntzer/numpy,jakirkham/numpy,endolith/numpy,pdebuyl/numpy,anntzer/numpy,rgommers/numpy,endolith/numpy,pdebuyl/numpy,seberg/numpy,seberg/numpy,mattip/numpy,simongibbons/numpy,mhvk/numpy,pdebuyl/numpy,simongibbons/numpy,jakirkham/numpy,rgommers/numpy,jakirkham/numpy,mattip/numpy,jakirkham/numpy,charris/numpy,pdebuyl/numpy,mhvk/numpy,mhvk/numpy,simongibbons/numpy,numpy/numpy,mhvk/numpy,rgommers/numpy,rgommers/numpy,anntzer/numpy,jakirkham/numpy,mhvk/numpy,simongibbons/numpy,numpy/numpy,endolith/numpy,endolith/numpy,seberg/numpy,numpy/numpy,charris/numpy,charris/numpy,numpy/numpy,charris/numpy,anntzer/numpy