Diffing text directly

[Raz-Hemo]

I might have missed it (no docs), but it seems like there is no way to compare text that is not part of a git repo, something like https://www.diffchecker.com/

If this is really not a feature it would be nice to have it. i'm not sure if diffy is a minimalist git-only thing intentionally, but if not I could attempt the implementation.

[seatedro]

This would be cool and as part of diffy's core ideology of VCS-agnostic, i think that should include NO VCS as well :)

Feel free to open a PR!