Generate all Ruby versions' documentation with the latest (released) RDoc

I recently made quite a few theme improvements to RDoc, along with community contributed changes like SEO tags...etc., which are all applied to the master documentation (https://docs.ruby-lang.org/en/master/index.html).
But since most of users will still be using Ruby 3.3 and prior versions for years to come, I think it'd be better if we can apply the same changes to their documentation too. I'd appreciate some pointers or even collaborations to make that happen. Thank you 🙂

将 docs.ruby-lang.org/en/master/index.html 中的 master 文档与 Ruby 3.3 及更早版本的版本化文档进行比较，以确定生成方面的差异。然后检查此仓库的文档生成入口点，并确定如何将最新发布的 RDoc 应用于受支持的 Ruby 版本；当版本化站点包含所请求的 theme 和 SEO 改进时，即视为完成。