Reference to steipete/bird which no longer exists publicly

[tris]

I'll just let this speak for itself:

Something went wrong
Stream failed: Unable to fetch tweet content from X. Bird not available. Nitter failed: Failed to fetch HTML document (status 403). Tip: Install bird🐦 for better Twitter support: https://github.com/steipete/bird

Related: steipete/homebrew-tap#13

Thanks for the extension, by the way -- loving it so far :)