chore: Replace MSRV link on main page with Github badge (#16020)

* Replace MSRV link on main page with Github badge

Author: comphead

README.md

@@ -26,6 +26,7 @@
 [![Open Issues][open-issues-badge]][open-issues-url]
 [![Discord chat][discord-badge]][discord-url]
 [![Linkedin][linkedin-badge]][linkedin-url]
+![Crates.io MSRV][msrv-badge]
 
 [crates-badge]: https://img.shields.io/crates/v/datafusion.svg
 [crates-url]: https://crates.io/crates/datafusion
@@ -40,6 +41,7 @@
 [open-issues-url]: https://github.com/apache/datafusion/issues
 [linkedin-badge]: https://img.shields.io/badge/Follow-Linkedin-blue
 [linkedin-url]: https://www.linkedin.com/company/apache-datafusion/
+[msrv-badge]: https://img.shields.io/crates/msrv/datafusion?label=Min%20Rust%20Version
 
 [Website](https://datafusion.apache.org/) |
 [API Docs](https://docs.rs/datafusion/latest/datafusion/) |
@@ -133,20 +135,6 @@ Optional features:
 [apache avro]: https://avro.apache.org/
 [apache parquet]: https://parquet.apache.org/
 
-## Rust Version Compatibility Policy
-
-The Rust toolchain releases are tracked at [Rust Versions](https://releases.rs) and follow
-[semantic versioning](https://semver.org/). A Rust toolchain release can be identified
-by a version string like `1.80.0`, or more generally `major.minor.patch`.
-
-DataFusion's supports the last 4 stable Rust minor versions released and any such versions released within the last 4 months.
-
-For example, given the releases `1.78.0`, `1.79.0`, `1.80.0`, `1.80.1` and `1.81.0` DataFusion will support 1.78.0, which is 3 minor versions prior to the most minor recent `1.81`.
-
-Note: If a Rust hotfix is released for the current MSRV, the MSRV will be updated to the specific minor version that includes all applicable hotfixes preceding other policies.
-
-DataFusion enforces MSRV policy using a [MSRV CI Check](https://github.com/search?q=repo%3Aapache%2Fdatafusion+rust-version+language%3ATOML+path%3A%2F%5ECargo.toml%2F&type=code)
-
 ## DataFusion API Evolution and Deprecation Guidelines
 
 Public methods in Apache DataFusion evolve over time: while we try to maintain a

docs/source/user-guide/introduction.md

@@ -184,3 +184,17 @@ provide integrations with other systems, some of which are described below:
 - _Easy to Connect_: Being part of the Apache Arrow ecosystem (Arrow, Parquet, and Flight), DataFusion works well with the rest of the big data ecosystem
 - _Easy to Embed_: Allowing extension at almost any point in its design, and published regularly as a crate on [crates.io](http://crates.io), DataFusion can be integrated and tailored for your specific usecase.
 - _High Quality_: Extensively tested, both by itself and with the rest of the Arrow ecosystem, DataFusion can and is used as the foundation for production systems.
+
+## Rust Version Compatibility Policy
+
+The Rust toolchain releases are tracked at [Rust Versions](https://releases.rs) and follow
+[semantic versioning](https://semver.org/). A Rust toolchain release can be identified
+by a version string like `1.80.0`, or more generally `major.minor.patch`.
+
+DataFusion supports the last 4 stable Rust minor versions released and any such versions released within the last 4 months.
+
+For example, given the releases `1.78.0`, `1.79.0`, `1.80.0`, `1.80.1` and `1.81.0` DataFusion will support 1.78.0, which is 3 minor versions prior to the most minor recent `1.81`.
+
+Note: If a Rust hotfix is released for the current MSRV, the MSRV will be updated to the specific minor version that includes all applicable hotfixes preceding other policies.
+
+DataFusion enforces MSRV policy using a [MSRV CI Check](https://github.com/search?q=repo%3Aapache%2Fdatafusion+rust-version+language%3ATOML+path%3A%2F%5ECargo.toml%2F&type=code)