docs: enable #![cfg_attr(docsrs, feature(doc_cfg))] to allow rustdoc feature display

Author: jlizen

lambda-events/src/lib.rs

@@ -1,4 +1,5 @@
 #![deny(rust_2018_idioms)]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 #[cfg(feature = "http")]
 pub use http;
 #[cfg(feature = "query_map")]

lambda-extension/src/lib.rs

@@ -1,6 +1,7 @@
 #![deny(clippy::all, clippy::cargo)]
 #![allow(clippy::multiple_crate_versions, clippy::type_complexity)]
 #![warn(missing_docs, nonstandard_style, rust_2018_idioms)]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 
 //! This module includes utilities to create Lambda Runtime Extensions.
 //!

lambda-http/src/lib.rs

@@ -1,4 +1,5 @@
 #![warn(missing_docs, rust_2018_idioms)]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 //#![deny(warnings)]
 //! Enriches the `lambda` crate with [`http`](https://github.com/hyperium/http)
 //! types targeting AWS [ALB](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/introduction.html), [API Gateway](https://docs.aws.amazon.com/apigateway/latest/developerguide/welcome.html) REST and HTTP API lambda integrations.

lambda-runtime-api-client/src/lib.rs

@@ -1,6 +1,7 @@
 #![deny(clippy::all, clippy::cargo)]
 #![warn(missing_docs, nonstandard_style, rust_2018_idioms)]
 #![allow(clippy::multiple_crate_versions)]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 
 //! This crate includes a base HTTP client to interact with
 //! the AWS Lambda Runtime API.

lambda-runtime/src/lib.rs

@@ -1,6 +1,7 @@
 #![deny(clippy::all, clippy::cargo)]
 #![allow(clippy::multiple_crate_versions)]
 #![warn(missing_docs, nonstandard_style, rust_2018_idioms)]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 
 //! The mechanism available for defining a Lambda function is as follows:
 //!