Add docs about array path params

[kciesielski]

Initial issue: We'd like to allow path params like .path[List[T]]("paramName") (https://swagger.io/docs/specification/serialization/) Related discussion on community forum: https://softwaremill.community/t/path-parameter-style-support/411 I don't think there's proper support for this in Tapir nor an issue already registered for this feature.

Update: Turns out it's feasible with Delimited, so this issue becomes a task to add documentation.