Release a new version for Ruby 4.0

[Earlopain]

Ruby 4.0 will be released soon. We should release a new version so that ruby 4.0 contains something that is available on rubygems.

Note: Gem sync has been disabled, so it will need to be copied over manually ruby/ruby@2117e61

[Earlopain]

Preliminary changelog (should contain #3817 so that ruby/ruby can branch to 4.1 without issues):

### Added

- Support `4.1` as a version option.
- Add `equal_loc` to `CallNode`.
- Add `len()`/`is_empty()` to `ConstantList` and `NodeList` in the Rust API.

### Changed

- Rename version `3.5` to version `4.0`.
- Fix compiling the gem from source on Windows.
- Fix parsing of unary method calls like `42.~@`.
- Reject `def f a, (b) = 1`.
- Reject endless method as a block parameter default.
- Reject variable capture in alternative pattern.
- Many fixes in regards to memory safety, found through fuzzing.
- Many fixes to better handle invalid syntax, also found through fuzzing.
- Fix the ruby version used by the `ripper` translator.
- Fix `ruby_parser` translation comment processing.

@kddnewton will you handle this? I can try following the release docs but would need someone to approve the bump PR, and I'm unsure if I can create tags.

[kddnewton]

Yeah no problem, I was going to do that this morning.