Improve docs for select multiple (#9539)

* Readd original select multiple note

* Update forms.md

docs/forms.md

@@ -182,6 +182,14 @@ class FlavorForm extends React.Component {
 
 Overall, this makes it so that `<input type="text">`, `<textarea>`, and `<select>` all work very similarly - they all accept a `value` attribute that you can use to implement a controlled component.
 
+> Note
+>
+> You can pass an array into the `value` attribute, allowing you to select multiple options in a `select` tag:
+>
+>```js
+><select multiple={true} value={['B', 'C']}>
+>```
+
 ## Handling Multiple Inputs
 
 When you need to handle multiple controlled `input` elements, you can add a `name` attribute to each element and let the handler function choose what to do based on the value of `event.target.name`.