add ALT-BACKSPACE to crossterm's to_input_request

[micielski]

ALT-BACKSPACE deletes previous word for various terminal apps like fish or helix editor (I think this keybinding comes from emacs so bash probably respects this keybinding by default too).

I see that there's also a corresponding function for termion, but it doesn't functionally correspond to crossterm's implementation nor isn't documented on docs.rs (both of which issues I could try to tackle in a new PR)

[sayanarijit]

Hi, I have checked, emacs and zsh supports alt-backspace, bash doesn't. But I'm good to add it.
But from my experiments, none supports meta-backspace for delete word.

[micielski]

But from my experiments, none supports meta-backspace for delete word.

I can remove meta-backspace if you want me to (it was there already and I didn't add it)

[sayanarijit]

Ah sorry, you're right. Thanks for the PR.