truncating-arraystring

ArrayString wrapper with truncating Write.

```rust use std::fmt::Write; use truncating_arraystring::TruncatingArrayString;

fn main() { let mut buf = TruncatingArrayString::<5>::new(); asserteq!(write!(buf, "{}", "12"), Ok(())); asserteq!(write!(buf, "{}", "3456789"), Err(std::fmt::Error)); assert_eq!(&buf.0[..], "12345"); } ```