Document the loadModel(path, normalize) overload

docs/parameterData.json

@@ -962,6 +962,12 @@
           "function(p5.Geometry)?",
           "function(Event)?"
         ],
+        [
+          "String|Request",
+          "Boolean?",
+          "function(p5.Geometry)?",
+          "function(Event)?"
+        ],
         [
           "String|Request",
           "String?",

src/webgl/loading.js

@@ -530,6 +530,14 @@ function loading(p5, fn) {
    *   console.error('Oops!', error);
    * }
    */
+  /**
+   * @method loadModel
+   * @param  {String|Request} path
+   * @param  {Boolean} [normalize]
+   * @param  {function(p5.Geometry)} [successCallback]
+   * @param  {function(Event)} [failureCallback]
+   * @return {Promise<p5.Geometry>} new <a href="#/p5.Geometry">p5.Geometry</a> object.
+   */
   /**
    * @method loadModel
    * @param  {String|Request} path

test/unit/core/param_errors.js

@@ -380,6 +380,26 @@ suite('Validate Params', function () {
     });
   });
 
+  suite('validateParams: loadModel normalize overload', function () {
+    const onLoad = () => {};
+    test('loadModel(): accepts normalize as the second argument', function () {
+      const result = mockP5Prototype._validate('p5.loadModel', ['model.obj', true]);
+      assert.isTrue(result.success);
+    });
+    test('loadModel(): accepts normalize followed by a callback', function () {
+      const result = mockP5Prototype._validate('p5.loadModel', ['model.obj', true, onLoad]);
+      assert.isTrue(result.success);
+    });
+    test('loadModel(): still accepts a file type and normalize', function () {
+      const result = mockP5Prototype._validate('p5.loadModel', ['model', '.obj', true]);
+      assert.isTrue(result.success);
+    });
+    test('loadModel(): still rejects a number as the second argument', function () {
+      const result = mockP5Prototype._validate('p5.loadModel', ['model.obj', 5]);
+      assert.isFalse(result.success);
+    });
+  });
+
   suite('validateParams: variadic min/max', function () {
     ['min', 'max'].forEach(fn => {
       test(`${fn}(): works with two numbers`, function () {