Option to call custom formatters on each entry (maybe it is added, just missing in doc)

[Casperhr]

Right now I have to do something like this

    var node = try paginator.makeNode()
        let data = node["data"]?.nodeArray
        var newData: [Node] = []
        
        for item in data! {
            let message = try ListingMessage(node: item)
            try newData.append(message.makeJSON(authedUser: request.lbUser(), imageSize: imageSize, thumbnailSize: thumbnailSize, backendUserSize: backendUserSize).node)
        }
        
        node["data"] = try Node(node: newData)
        
        // TODO Figure out a way to format easier