Support both bzlmod and nix in start script #2204
Description
Is your feature request related to a problem? Please describe.
The start script doesn't support both --use-nix and --with-bzlmod=true.
Describe the solution you'd like
The script to support it!
Describe alternatives you've considered
Additional context
@LiamGoodacre and I have been working on an example that uses both bzlmod and nix at https://github.com/jonathanlking/rules-haskell-bzlmod-nix, which I intend to open a PR to update the start script to output.