[BUG]: Ensure order when manipulating ` .tool-versions`

[aooohan]

          Will this also fix the random reordering that occurs in .tool-versions when rebuilding a devcontainer? The versions don't change, just for example if I have elixir and erlang installed, sometimes erlang will be on top, sometimes elixir. I can create a separate issue if this isn't related.

Originally posted by @ccavolt in https://github.com/version-fox/vfox/issues/277#issuecomment-2125147977