Add documentation on descriptor set

README.md

@@ -91,6 +91,22 @@ by the registered handler, proxied through the docs handler.
 
 Also see a full example [here](./examples/grpc).
 
+### Descriptor Set
+
+The docs handler can utilize a serialized descriptor set to augment documentation with the comments
+from a proto source file. It is strongly recommended to do this to make the documentation more
+useful.
+
+A descriptor set can be generated by protoc together with any other code. Source info and imports must
+be included.
+
+```bash
+protoc --descriptor_set_out=descriptors.pb --include_source_info --include_imports --proto_path=. --go_out=. greet.proto
+```
+
+The serialized descriptors can be loaded with the `WithSerializedDescriptors` option when initializing a
+plugin. It is recommended to `go:embed` them into the binary to ensure they are accessible.
+
 [0]: https://armeria.dev
 [1]: https://connectrpc.com/docs/go
 [2]: https://github.com/grpc/grpc-go