extend CompactStringExt implementation

[asibahi]

Hello.

I have been converting my discord bot to use CompactString throughout, mostly because I have nothing better to do tbh.

There is this snippet of code :

minion_types
    .iter()
    .map(|t| t.in_locale(self.1)) // `in_locale` returns `impl Display`
    .join("/") // <-- from itertools
    .to_compact_string()

I tried playing with it in different ways to avoid the String creation in the middle by join, but join_compact is not apparently implemented for Map.

For example when I change it to this

minion_types
    .iter()
    .map(|t| t.in_locale(self.1).to_compact_string()) // not sure what to do here.
    .join_compact("/")

I get this extra verbose error

error[E0599]: the method `join_compact` exists for struct `Map<Iter<'_, MinionType>, {[email protected]:161:10}>`, but its trait bounds were not satisfied
   --> mimiron/src/bg.rs:162:6
    |
159 | / minion_types
160 | |     .iter()
161 | |     .map(|t| t.in_locale(self.1).to_compact_string())
162 | |     .join_compact("/")
    | |     -^^^^^^^^^^^^ method cannot be called on `Map<Iter<'_, MinionType>, {[email protected]:161:10}>` due to unsatisfied trait bounds
    | |_____|
    |
    |
   ::: /Users/abdulrahmansibahi/.rustup/toolchains/stable-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/adapters/map.rs:61:1
    |
61  |   pub struct Map<I, F> {
    |   -------------------- doesn't satisfy `_: CompactStringExt`
    |
    = note: the following trait bounds were not satisfied:
            `<&'a std::iter::Map<std::collections::hash_set::Iter<'_, card_details::MinionType>, {closure@mimiron/src/bg.rs:161:10: 161:13}> as std::iter::IntoIterator>::Item = &'a _`
            which is required by `std::iter::Map<std::collections::hash_set::Iter<'_, card_details::MinionType>, {closure@mimiron/src/bg.rs:161:10: 161:13}>: compact_str::CompactStringExt`
            `&'a std::iter::Map<std::collections::hash_set::Iter<'_, card_details::MinionType>, {closure@mimiron/src/bg.rs:161:10: 161:13}>: std::iter::IntoIterator`
            which is required by `std::iter::Map<std::collections::hash_set::Iter<'_, card_details::MinionType>, {closure@mimiron/src/bg.rs:161:10: 161:13}>: compact_str::CompactStringExt`

I do not if I am missing something obvious or if this is a missing implementation from the library.

[ParkMyCar]

Thanks for the bug report @asibahi! This is indeed an issue in the library, I just put up #418 to fix this and will release it with a v0.9