DOC: add note on flatten ordering in matlab page (#16001)
DOC: add note on flatten ordering in matlab page (#16001)

Add note on the ordering of matlab's ``x(:)`` vs NumPy ``x.flatten()``

fix #15837
anntzer/numpy,rgommers/numpy,mhvk/numpy,mhvk/numpy,jakirkham/numpy,simongibbons/numpy,pdebuyl/numpy,simongibbons/numpy,charris/numpy,grlee77/numpy,abalkin/numpy,mattip/numpy,charris/numpy,numpy/numpy,madphysicist/numpy,endolith/numpy,simongibbons/numpy,pdebuyl/numpy,endolith/numpy,pbrod/numpy,charris/numpy,anntzer/numpy,endolith/numpy,abalkin/numpy,pbrod/numpy,mhvk/numpy,mattip/numpy,madphysicist/numpy,pdebuyl/numpy,mattip/numpy,madphysicist/numpy,jakirkham/numpy,mhvk/numpy,pbrod/numpy,charris/numpy,anntzer/numpy,seberg/numpy,madphysicist/numpy,numpy/numpy,abalkin/numpy,rgommers/numpy,seberg/numpy,madphysicist/numpy,pbrod/numpy,mattip/numpy,grlee77/numpy,jakirkham/numpy,jakirkham/numpy,numpy/numpy,grlee77/numpy,rgommers/numpy,endolith/numpy,jakirkham/numpy,seberg/numpy,simongibbons/numpy,pbrod/numpy,grlee77/numpy,mhvk/numpy,anntzer/numpy,simongibbons/numpy,pdebuyl/numpy,grlee77/numpy,rgommers/numpy,seberg/numpy,numpy/numpy