Fix doc build in subproject

msg_tool_macro/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "msg_tool_macro"
-version = "0.2.1"
+version = "0.2.9"
 edition = "2024"
 repository = "https://github.com/lifegpc/msg-tool"
 description = "A procedural macro for the msg-tool project."

msg_tool_macro/src/lib.rs

@@ -1,4 +1,4 @@
-#![cfg_attr(any(docsrs, feature = "unstable"), feature(doc_auto_cfg))]
+#![cfg_attr(any(docsrs, feature = "unstable"), feature(doc_cfg))]
 use proc_macro::TokenStream;
 use syn::parse::discouraged::Speculative;
 use syn::spanned::Spanned;