DOC: use ELLIPSIS in error message and add note about copying
DOC: use ELLIPSIS in error message and add note about copying

Co-authored-by: Matti Picus <faf711dbf9cf26dd81c70c606be887f6131932db@gmail.com>

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