docs: add axum-insights to relevant crates. (tokio-rs#2713)

## Motivation

Adding a relevant library to the list of `tracing`-enabled crates.

## Solution

Added to READMEs and documentation.

README.md

@@ -371,6 +371,7 @@ are not maintained by the `tokio` project. These include:
 - [`tracing-actix-web`] provides `tracing` integration for the `actix-web` web framework.
 - [`tracing-actix`] provides `tracing` integration for the `actix` actor
   framework.
+- [`axum-insights`] provides `tracing` integration and Application insights export for the `axum` web framework.
 - [`tracing-gelf`] implements a subscriber for exporting traces in Greylog
   GELF format.
 - [`tracing-coz`] provides integration with the [coz] causal profiler
@@ -415,6 +416,7 @@ please let us know!)
 [honeycomb.io]: https://www.honeycomb.io/
 [`tracing-actix`]: https://crates.io/crates/tracing-actix
 [`tracing-actix-web`]: https://crates.io/crates/tracing-actix-web
+[`axum-insights`]: https://crates.io/crates/axum-insights
 [`tracing-gelf`]: https://crates.io/crates/tracing-gelf
 [`tracing-coz`]: https://crates.io/crates/tracing-coz
 [coz]: https://github.com/plasma-umass/coz

tracing/README.md

@@ -361,6 +361,7 @@ maintained by the `tokio` project. These include:
 - [`tracing-distributed`] Provides a generic implementation of a layer that reports traces spanning multiple machines to some backend.
 - [`tracing-actix`] provides `tracing` integration for the `actix` actor
   framework.
+- [`axum-insights`] provides `tracing` integration and Application insights export for the `axum` web framework.
 - [`tracing-gelf`] implements a subscriber for exporting traces in Greylog
   GELF format.
 - [`tracing-coz`] provides integration with the [coz] causal profiler
@@ -389,6 +390,7 @@ please let us know! We'd love to add your project to the list!
 [`tracing-distributed`]: https://crates.io/crates/tracing-distributed
 [honeycomb.io]: https://www.honeycomb.io/
 [`tracing-actix`]: https://crates.io/crates/tracing-actix
+[`axum-insights`]: https://crates.io/crates/axum-insights
 [`tracing-gelf`]: https://crates.io/crates/tracing-gelf
 [`tracing-coz`]: https://crates.io/crates/tracing-coz
 [coz]: https://github.com/plasma-umass/coz

tracing/src/lib.rs

@@ -786,6 +786,7 @@
 //!  - [`tracing-actix-web`] provides `tracing` integration for the `actix-web` web framework.
 //!  - [`tracing-actix`] provides `tracing` integration for the `actix` actor
 //!    framework.
+//!  - [`axum-insights`] provides `tracing` integration and Application insights export for the `axum` web framework.
 //!  - [`tracing-gelf`] implements a subscriber for exporting traces in Greylog
 //!    GELF format.
 //!  - [`tracing-coz`] provides integration with the [coz] causal profiler
@@ -827,6 +828,7 @@
 //! [honeycomb.io]: https://www.honeycomb.io/
 //! [`tracing-actix-web`]: https://crates.io/crates/tracing-actix-web
 //! [`tracing-actix`]: https://crates.io/crates/tracing-actix
+//! [`axum-insights`]: https://crates.io/crates/axum-insights
 //! [`tracing-gelf`]: https://crates.io/crates/tracing-gelf
 //! [`tracing-coz`]: https://crates.io/crates/tracing-coz
 //! [coz]: https://github.com/plasma-umass/coz