chore(docsrs): make docs.rs build work

The nightly feature has been removed in rust 1.92, see docs.rs build
failure https://docs.rs/crate/rustls-native-certs/latest/builds/2773223
and rust PR rust-lang/rust#138907.

Also, renamed the cfg into `rustls_native_certs_docsrs`. See
rustls/rustls#2682 for more info.

Author: joshuachp

.github/workflows/rust.yml

@@ -142,7 +142,7 @@ jobs:
       - name: cargo doc (rustls; all features)
         run: cargo doc --locked --all-features --no-deps --document-private-items
         env:
-          RUSTDOCFLAGS: -Dwarnings
+          RUSTDOCFLAGS: -Dwarnings --cfg=rustls_native_certs_docsrs
 
   format:
     name: Format

Cargo.toml

@@ -32,3 +32,9 @@ openssl-probe = "0.2"
 
 [target.'cfg(target_os = "macos")'.dependencies]
 security-framework = "3"
+
+[lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = [ 'cfg(rustls_native_certs_docsrs)' ] }
+
+[package.metadata.docs.rs]
+rustdoc-args = ["--cfg", "rustls_native_certs_docsrs"]

src/lib.rs

@@ -19,7 +19,7 @@
 //! ```
 
 // Enable documentation for all features on docs.rs
-#![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
+#![cfg_attr(rustls_native_certs_docsrs, feature(doc_cfg))]
 
 use std::error::Error as StdError;
 use std::path::{Path, PathBuf};