Feature Request: yaml!() macro similar to serde_json::json!({})

[Fishrock123]

It would be great for purposes of templating and constructing yaml configs for other programs to have a nice way to declare lots of nested yaml in source code, similar to serde_json's json!({}) macro.

Of course we all know this sounds much easier than it is to do. It's a big ask but I hope the Rust community can get it some day.

[dtolnay]

I would prefer not to build this into this crate.

[Fishrock123]

So, best would be to have separate crate i.e. a theoretical serde_yaml_macro to house this functionality?