Extract Parameter from Wildcard Routes

[markdingram]

From https://docs.rs/axum/latest/axum/struct.Router.html#wildcards - a route like /assets/*path should extract a param.

There's a good old discussion with no concrete answer at OAI/OpenAPI-Specification#892 over precisely this should be represented in OpenAPI 3.X - from a quick scan the best approach could be to follow the AWS Gateway API style: /assets/{path+}

I can provide a PR?

[Wicpar]

Good idea ! We should strive to support all axum features.