Documents `NamedParams` attributes for Python

[MangelMaxime]

module Json =

    [<Erase>]
    type IExports =
        [<NamedParams(1)>]
        abstract dumps:
            obj: obj * ?separators: string array * ?indent: int -> string

    [<ImportAll("json")>]
    let json: IExports = nativeOnly

    [<Import("JSONDecodeError", "json")>]
    type JSONDecodeError() =
        inherit Exception()