Naming parameters in endpoint path

[pir2o61]

It seems that there is no way to name parameters in path (mainly for use in Swagger).
Something like {petId:%i} in https://github.com/hvester/EndpointBuilder will be very nice.

One way that it can be done is via changing convertToRouteTemplate function in EndpointRouting. Something like below should be enough:

            | '%' :: c :: tail ->
                let (placeholderName, placeholderTemplate), newTail = 
                    match tail with
                    | ':' :: stail ->
                        let splitIndex = stail |> List.tryFindIndex (fun c -> c = '/')
                        match splitIndex with
                        | Some splitIndex ->
                            let name , newTail = 
                                stail 
                                |> List.splitAt splitIndex
                            getConstraint i c (Some (System.String.Concat(Array.ofList(name)))), newTail
                        | None -> 
                            getConstraint i c (Some (System.String.Concat(Array.ofList(stail)))), []
                    | _ ->
                        getConstraint i c None, tail
                let template, mappings = convert (i + 1) newTail
                placeholderTemplate + template, (placeholderName, c) :: mappings

where getConstraint is changed like this

    let private getConstraint (i : int) (c : char) (name : string option) =
        let name = Option.defaultValue (sprintf "%c%i" c i) name

1. Do we want this feature?
2. On what scope it should work? (what names do we allow, do we want to have it in format %c:name. `name:%c' or different