Stable Extend::extend_one alternative

Alternative to Extend::extend_one that is stable and does not require #![feature(extend_one)].

Example

use proc_macro2 as pm2;
use extend1::Extend1;

let mut ts = pm2::TokenStream::new();
ts.extend1(pm2::Literal::string("Hello, world!"));
assert_eq!(ts.to_string(), "\"Hello, world!\"");

License

^{Licensed under either of Apache License, Version 2.0 or MIT license at your option.}
_{Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this crate by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.}