implement FromIterator<char> for ArrayString

[elichai]

Hi,
I want to use ArrayString in rustc_hex::ToHex, this trait works on every type that implements FromIterator on Item=char.
But ArrayString is Item=u8.

Is there a reason this isn't Item=char?

[clarfonthey]

ArrayString doesn't implement FromIterator at all. Presumably a PR adding this would be accepted.

[elichai]

So it's not that easy because ArrayString and ArrayVec are inherently different.
How do you think about making ArrayString just a wrapper of ArrayVec with the generic Array set to Array<Item=u8>? (just like String is a wrapper for Vec)

If so maybe i'll work on a PR

[bluss]

@elichai That won't work so well, ArrayString should be a wrapper around "ArrayVecCopy" (not yet implemented).

[chris-morgan]

Closely related is core::iter::Extend<A>, which String implements for A = char | Box<str> | String | &char | &str | Cow<str>.