Merge pull request #159 from rust-lang/docs-improve-docs.rs-docs

docs: improve docs.rs docs

service-catalog/docs-rs/REAMDE.md

@@ -5,11 +5,13 @@ Docs.rs is a service that hosts documentation of crates.
 The docs.rs codebase is available at [rust-lang/docs.rs] and
 it's maintained by the [docs.rs team](https://www.rust-lang.org/governance/teams/dev-tools#team-docs-rs).
 
-The codebase is deployed via the [terraform/docs-rs] module.
+The infrastructure is managed via the [terraform/docs-rs] module.
 
 The EC2 `docsrs.infra.rust-lang.org` is served by Cloudfront CDN at `docs.rs`.
 
-Docs.rs also uses the `rust-docs-rs` S3 bucket which is served by Cloudfront CDN at `static.docs.rs`.
+Docs.rs also uses the `rust-docs-rs` S3 bucket which is served
+through the docs.rs webserver itself, and additionally through the Cloudfront CDN `static.docs.rs`.
+Docs.rs rewrites the doc pages before serving them.
 
 [rust-lang/docs.rs]: https://github.com/rust-lang/docs.rs
 [terraform/docs-rs]: https://github.com/rust-lang/simpleinfra/tree/master/terraform/docs-rs