Target v8.1.2195 .
Nvim did not port Vim's ":terminal" opts.
Incompatible implementations.
Ex-command was ported from C to Lua.
Vim needs them partly because of splitting the current window.
I keep forgetting `++close` option so I either run ":qall!"
or kill the parent process (ie. terminal emulator).
Unsatisfied users should create their Ex-command that runs jobstart().