Added a generate example to rand api

Author: Sandstedt

docs/api/syntax/rand.md

@@ -14,4 +14,35 @@ Full API reference:
 
 ```
 
+::: tip
+If you wanna update the random value after it's been declared, you can use the `generate()` function:
+```js
+const example = new mojs.Burst({
+  radius:   { 'rand(4, 40)' : 'rand(50, 100)' }
+});
+
+document.addEventListener( 'click', function (e) {
+  example.generate().replay();
+});
+```
+:::
+
+<MojsInteractive
+  id="example"
+  autoplay
+  height="200px"
+  global="example"
+  code=
+"const example = new mojs.Burst({
+  radius:   { 'rand(4, 40)' : 'rand(50, 100)' }
+});
+
+document.addEventListener( 'click', function (e) {
+  example.generate().replay();
+});
+
+example.play();"
+>
+</MojsInteractive>
+
 - [CodePen Example](https://codepen.io/sandstedt/pen/dyXevEE?editors=0010)