Cleaner macros utilizing syn::Member

[Bleachfuel]

Objective

Some macros were handling Idents and indexes as seperate things, we can use syn::Member to make this more readable and nicer.

Testing

ran all revelant crate tests.

[Bleachfuel]

#[derive(QueryData)]
#[query_data(mutable(foo))]
//~^ ERROR: `mutable` does not take any arguments
struct MutableInvalidAttributeParameters {
    a: &'static mut Foo,
}

should we really give a error for this? seems so unnessesary and extra code. When u do this it already says "expected ,". I removed 2 of them, since the errors that syn gives are already clear. Maybe even clearer.

[chescock]

Yeah, this seems cleaner!

It's a little unfortunate that syn::Member doesn't have the rest of the Field value, forcing most of the uses here to do fields.iter().enumerate().filter().map() instead of just field.members(). Would it ever make sense to add our own wrapper type around a &Field and its index, along with a function to iterate them from a Fields, so that we could share a little more code here?

[Bleachfuel]

Yeah we could do that, but would be better as a follow up pr