[Live] Adding an example of a norender model with a button to trigger…

… the render

src/LiveComponent/doc/index.rst

@@ -370,6 +370,13 @@ it won't, yet, make an Ajax call to re-render the component. Whenever
 the next re-render *does* happen, the updated ``max`` value will be
 used.
 
+This can be useful along with a button that triggers a render on click:
+
+.. code-block:: html+twig
+
+    <input data-model="norender|coupon">
+    <button data-action="live#$render">Apply</button>
+
 .. _name-attribute-model:
 
 Using name="" instead of data-model