Expose RUBY_PATCHLEVEL_STR or similar with patch level info for rc/preview as a constant
When ruby is in release candidate or preview,
-1. Without parsing
RUBY_DESCRIPTION, its hard to tell using constant the right and absolute ruby version.
RUBY_PATCHLEVEL_STR as a constant, just like
RUBY_PATCHLEVEL. So that, we can know the right ruby version, especially when its in preview or release candidate. This is also helpful when using gems that rely on
RUBY_VERSION to serve the right experience. Example: Bundler, which validates gem installation by making sure right ruby is installed. Currently, we cannot install gems using 2.5.0preview1.
Your Ruby version is 2.5.0, but your Gemfile specified 2.5.0preview1
This can be handled in bundler through some different wokraround, but I think by exposing
RUBY_PATCHLEVEL_STR, it will be helpful in building the appropriate solutions.