Add trailing slash removal support when axum-extra feature is enabled

[Snapstromegon]

Axum-extra adds the convenient _with_tsr() methods to e.g. the router: https://docs.rs/axum-extra/0.9.3/axum_extra/routing/trait.RouterExt.html#tymethod.route_with_tsr

I use these quite frequently and haven't found a way to use those with the aide ApiRouter even when the axum-extra feature is enabled. Is it possible/feasable to add support for this to aide?

[tamasfe]

The RouterExt trait from axum-extra is missing from aide completely, it would be a welcome addition.