Support Croissant REPL for Lua

[IndianBoy42]

Is your feature request related to a problem? Please describe.

The 'inbuilt' lua repl lua and luap are not very nice to work in, i recently found croissant which is a lot more user friendly. neoterm currently supports choosing a python repl using vim.g.neoterm_repl_python, this could be extended to lua

Describe the solution you'd like

setting vim.g.neoterm_repl_lua = croissant should make neoterm launch croissant when I send lines from a lua file.

It would also be possible to add variables for all languages to allow the user to override any repl they want. If overriden we would have to assume/set some basic behaviour like how to run a line in a repl (usually just type the line then hit enter), how to handle newlines and multiline commands (some repls may use shift-enter, some may not support at all and we should just send as individual lines), etc.

Describe alternatives you've considered
Manually launching :T croissant first, because neoterm won't try launch the repl except on startup

[kassio]

Hi there, thanks for the issue. Can you try to open a pull request for that please? You can check https://github.com/kassio/neoterm/blob/master/ftdetect/set_repl_cmd.vim#L5 for reference.