Function space_between

fn space_between(tt1: &TokenTree, tt2: &TokenTree) -> bool

Should two consecutive tokens be printed with a space between them?

Note: some old proc macros parse pretty-printed output, so changes here can break old code. For example:

• #63896: #[allow(unused, must be printed rather than #[allow(unused ,
• #73345: #[allow(unused)] must be printed rather than # [allow(unused)]