Format MacroDef (macros 2.0)

[nrc]

Should share code with macro_rules I imagine. See FIXME in visitor.rs.

[topecongiro]

What kind of formatting is intended inside MacroDef or macro_rules?

[nrc]

There is already some formatting for macro_rules, and we should copy that for macros 2.0. Basically what we do for now is see if the macro 'looks like' some other kind of AST node (function call or array initialiser are the only things we check for, I think) and if so, format like that. Otherwise we try to align the macro call, but don't otherwise reformat.

[crlf0710]

Currently

pub(crate) fn z1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890(a: u32, b: u32) -> u32 {}

pub(crate) macro z1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890($a:expr, $b:expr) {}

The function got reformated, but macro doesn't got reformated. It would be nice if it can respect the line width limit at least.

[elenakrittik]

Hi! Any progress or blockers for this?