clarify svd documentation
clarify svd documentation

`u @ np.diag(s) @ vh` can only reproduce the original matrix when `full_matrices` is `False`, otherwise dimension does not match.
mhvk/numpy,mhvk/numpy,charris/numpy,pdebuyl/numpy,pdebuyl/numpy,mattip/numpy,endolith/numpy,mhvk/numpy,charris/numpy,numpy/numpy,mhvk/numpy,jakirkham/numpy,jakirkham/numpy,mhvk/numpy,endolith/numpy,anntzer/numpy,endolith/numpy,charris/numpy,anntzer/numpy,seberg/numpy,pdebuyl/numpy,pdebuyl/numpy,jakirkham/numpy,rgommers/numpy,anntzer/numpy,rgommers/numpy,seberg/numpy,numpy/numpy,jakirkham/numpy,jakirkham/numpy,mattip/numpy,rgommers/numpy,charris/numpy,endolith/numpy,numpy/numpy,anntzer/numpy,rgommers/numpy,seberg/numpy,numpy/numpy,mattip/numpy,seberg/numpy,mattip/numpy