Wrong entrypoint target in installer for NodeJS bundlers

[julianrubisch]

Hey 👋

Thank you a lot for this simple yet effective package.

In https://github.com/skryukov/turbo-mount/blob/main/lib/generators/turbo_mount/install_generator.rb#L57, the entrypoint to which to append to is referencing app/javascript/entrypoints/application.js, which is not correct in a stock Rails app (it should point to app/javascript/application.js as in the importmap case).

I don't know if this is intentional, but even if it is, a heads up emitted by the generator would be nice in case it can't find the entrypoint to go and add import "./turbo-mount" manually.