Make vim9script file executable for neovim

[tjdevries]

• [ ] Take in a .vim file
• [ ] Handle vim9script files:
  • [ ] Transform the entire file into a big lua << END heredoc block that can be executed in vim
  • [ ] Make sure all of the functions and side effects happen
• [ ] handle def within a vimscript file:
  • [ ] Have to find all the def functions
  • [ ] Transpile those individiually into lua blocks.
  • [ ] Make sure that we have access to the same script state and other items
  • [ ] Make sure to still be able to export other stuff as well