Test the output of `to_lua` with `stylua`

[vil02]

#391 added the to_lua.

It is worth testing if the output is properly formatted with stylua.

What needs to be done:

• modify the function run_lua_code:
  

  string_to_code_proj/tests/setup_lua.py

  Line 24 in cb5d084

  def run_lua_code(in_code, tmp_folder):

  
  to run stylua --check on the temporary source file (i.e. tmp_folder / source_filename),
• install stylua in setup_for_lua.sh.