Allow controlling addon block return shape

src/engine/runtime.js

@@ -2588,7 +2588,8 @@ class Runtime extends EventEmitter {
      * @param {string} options.procedureCode The ID of the block
      * @param {function} options.callback The callback, called with (args, BlockUtility). May return a promise.
      * @param {string[]} [options.arguments] Names of the arguments accepted. Optional if no arguments.
-     * @param {boolean} [hidden] True to not include this block in the block palette
+     * @param {boolean} [options.hidden] True to not include this block in the block palette
+     * @param {1|2} [options.return] 1 for round reporter, 2 for boolean reported, leave empty for statement.
      */
     addAddonBlock (options) {
         const procedureCode = options.procedureCode;
@@ -2633,6 +2634,7 @@ class Runtime extends EventEmitter {
                     ` argumentnames="${xmlEscape(JSON.stringify(names))}"` +
                     ` argumentids="${xmlEscape(JSON.stringify(ids))}"` +
                     ` argumentdefaults="${xmlEscape(JSON.stringify(defaults))}"` +
+                    `${options.return ? ` return="${xmlEscape(options.return.toString())}"` : ''}` +
                     '></mutation></block>'
             });
         }