chore(upnp, webrtc): add missing docs.rs metadata

Includes necessary package metadata to improve documentation on docs.rs (shows which items are behind a cfg).
Read more on: libp2p#2983

Pull-Request: libp2p#4599.

Author: umgefahren

protocols/upnp/Cargo.toml

@@ -25,3 +25,10 @@ tokio = ["igd-next/aio_tokio", "dep:tokio"]
 
 [lints]
 workspace = true
+
+# Passing arguments to the docsrs builder in order to properly document cfg's.
+# More information: https://docs.rs/about/builds#cross-compiling
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]
+rustc-args = ["--cfg", "docsrs"]

transports/webrtc/Cargo.toml

@@ -48,3 +48,10 @@ required-features = ["tokio"]
 
 [lints]
 workspace = true
+
+# Passing arguments to the docsrs builder in order to properly document cfg's.
+# More information: https://docs.rs/about/builds#cross-compiling
+[package.metadata.docs.rs]
+all-features = true
+rustdoc-args = ["--cfg", "docsrs"]
+rustc-args = ["--cfg", "docsrs"]

transports/webrtc/src/lib.rs

@@ -79,5 +79,8 @@
 //! hand-crate the SDP answer generated by the remote, this is problematic. A way to solve this
 //! is to make the hash a part of the remote's multiaddr. On the server side, we turn
 //! certificate verification off.
+
+#![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
+
 #[cfg(feature = "tokio")]
 pub mod tokio;