Add docs

Author: CrisBarreiro

js-messaging/js-messaging-api/src/main/java/com/duckduckgo/js/messaging/api/AdsjsMessaging.kt

@@ -51,6 +51,18 @@ interface AdsjsMessaging {
 }
 
 interface AdsjsJsMessageCallback {
+    /**
+     * Processes a JavaScript message received by the WebView.
+     *
+     * This method is responsible for handling a message with the given parameters
+     * and invoking a callback to send a response back to the JavaScript code.
+     *
+     * @param featureName The name of the feature associated with the message.
+     * @param method The method name of the message.
+     * @param id An optional identifier for the message.
+     * @param data An optional JSON object containing additional data for the message.
+     * @param onResponse A callback function to send a response back to the JavaScript code.
+     */
     fun process(
         featureName: String,
         method: String,
@@ -69,6 +81,7 @@ interface AdsjsMessageHandler {
      *
      * @param jsMessage The JavaScript message to be processed.
      * @param jsMessageCallback An optional callback to handle the result of the message processing.
+     * @param onResponse A callback function to send a response back to the JavaScript code.
      */
     fun process(
         jsMessage: JsMessage,