Eglot: Add ruff-lsp as an alternative Python server

Eglot: Add ruff-lsp as an alternative Python server

ruff-lsp [1] is an LSP server for Ruff [2], [3], a fast Python linter
and code formatter.

It supports surfacing Ruff diagnostics and providing Code Actions to
fix them, but is intended to be used alongside another Python LSP in
order to support features like navigation and autocompletion.

[1]: https://github.com/astral-sh/ruff-lsp
[2]: https://github.com/astral-sh/ruff
[3]: https://docs.astral.sh/ruff/

* lisp/progmodes/eglot.el (eglot-server-programs): Add ruff-lsp.

Copyright-paperwork-exempt: yes