Update readme.md for the legacy crates

Author: Fahad Zubair

rust-runtime/aws-smithy-legacy-http-server/README.md

@@ -1,7 +1,13 @@
-# aws-smithy-http-server
+# aws-smithy-legacy-http-server
+
+**This is a legacy crate that provides support for `http@0.x` and `hyper@0.x`.**
 
 Server libraries for smithy-rs generated servers.
 
+## Usage
+
+This crate is used when generating server SDKs without the `http-1x` codegen flag. For new projects, prefer using `aws-smithy-http-server` which supports `http@1.x` and `hyper@1.x`.
+
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 This crate is part of the [AWS SDK for Rust](https://awslabs.github.io/aws-sdk-rust/) and the [smithy-rs](https://github.com/smithy-lang/smithy-rs) code generator. In most cases, it should not be used directly.
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rust-runtime/aws-smithy-legacy-http/README.md

@@ -1,4 +1,6 @@
-# aws-smithy-http
+# aws-smithy-legacy-http
+
+**This is a legacy crate that provides support for `http@0.x` and `hyper@0.x`.**
 
 Core HTTP primitives for service clients generated by [smithy-rs](https://github.com/smithy-lang/smithy-rs) including:
 - HTTP Body implementation
@@ -7,6 +9,10 @@ Core HTTP primitives for service clients generated by [smithy-rs](https://github
 - Event streams
 - `ByteStream`: _(supported on crate feature `rt-tokio` only)_ a misuse-resistant abstraction for streaming binary data
 
+## Usage
+
+This crate is used when generating server SDKs without the `http-1x` codegen flag. For new projects, prefer using `aws-smithy-http` which supports `http@1.x` and `hyper@1.x`.
+
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 This crate is part of the [AWS SDK for Rust](https://awslabs.github.io/aws-sdk-rust/) and the [smithy-rs](https://github.com/smithy-lang/smithy-rs) code generator. In most cases, it should not be used directly.
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