Improve how we detect Rails apps

[andyw8]

Description

Currently we look for a dependency on the Rails gem, and if found, we assume a Rails app is present, and add "ruby-lsp-rails" to the custom bundle. But this approach can result in false positives. Instead, we should check the presence of bin/rails.

[github-actions]

This issue is being marked as stale because there was no activity in the last 2 months

[andyw8]

Done in #1896