<Plug>(edgemotion-j) and <Plug>(edgemotion-k) motion is like j, k, but stops at edge only.
Inspired by EdgeMotion in atom-vim-mode-plus
vmp: the most ambitious vim emulator
map <C-j> <Plug>(edgemotion-j)
map <C-k> <Plug>(edgemotion-k)haya14busa (https://github.com/haya14busa)