Enable bracketed paste

[ulyssa]

The crossterm crate supports reading bracketed paste commands from terminals that support it. This allows differentiating between newlines sent from pressing <Enter> and newlines that are part of pasted text. When iamb receives a bracketed paste, it should insert the text without interpreting it as typed characters, since that is most likely what the user wanted.

Note that this won't work everywhere: terminal multiplexers like screen will sometimes sanitize different escape sequences, so it will be up to users who want bracketed paste to ensure they're running in an environment where it will work.