Resolve stable_features warning on proc_macro_raw_ident

    warning: the feature `proc_macro_raw_ident` has been stable since 1.47.0 and no longer requires an attribute to enable
      --> src/lib.rs:83:37
       |
    83 | #![cfg_attr(super_unstable, feature(proc_macro_raw_ident, proc_macro_def_site))]
       |                                     ^^^^^^^^^^^^^^^^^^^^
       |
       = note: `#[warn(stable_features)]` on by default

src/lib.rs

@@ -80,7 +80,7 @@
 // Proc-macro2 types in rustdoc of other crates get linked to here.
 #![doc(html_root_url = "https://docs.rs/proc-macro2/1.0.29")]
 #![cfg_attr(any(proc_macro_span, super_unstable), feature(proc_macro_span))]
-#![cfg_attr(super_unstable, feature(proc_macro_raw_ident, proc_macro_def_site))]
+#![cfg_attr(super_unstable, feature(proc_macro_def_site))]
 #![cfg_attr(doc_cfg, feature(doc_cfg))]
 #![allow(
     clippy::cast_lossless,