Use of proc_macro_hack breaks rust-analyzer

[rib]

It would be great if the use of proc_macro_hack can be removed so that sexpr! can be used reliably with rust-analyzer.

E.g. something like this: https://github.com/ilya-klyuchnikov/lexpr-rs/commit/3ef88458e4f7bf88cda33e749a95fa0351014119

ref: https://github.com/rust-analyzer/rust-analyzer/issues/6835

also from the proc-macro-hack repo:

Note: As of Rust 1.45 this crate is superseded by native support for #[proc_macro] in expression position. Only consider using this crate if you care about supporting compilers between 1.31 and 1.45.