[Switch] Add missing parameter to docs

The `onChange` function signature in Switch api documentation was missing the second `checked` parameter.

docs/pages/api-docs/switch.md

@@ -39,7 +39,7 @@ The `MuiSwitch` name can be used for providing [default props](/customization/gl
 | <span class="prop-name">id</span> | <span class="prop-type">string</span> |  | The id of the `input` element. |
 | <span class="prop-name">inputProps</span> | <span class="prop-type">object</span> |  | [Attributes](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input#Attributes) applied to the `input` element. |
 | <span class="prop-name">inputRef</span> | <span class="prop-type">ref</span> |  | Pass a ref to the `input` element. |
-| <span class="prop-name">onChange</span> | <span class="prop-type">func</span> |  | Callback fired when the state is changed.<br><br>**Signature:**<br>`function(event: object) => void`<br>*event:* The event source of the callback. You can pull out the new value by accessing `event.target.value` (string). You can pull out the new checked state by accessing `event.target.checked` (boolean). |
+| <span class="prop-name">onChange</span> | <span class="prop-type">func</span> |  | Callback fired when the state is changed.<br><br>**Signature:**<br>`function(event: object, checked: boolean) => void`<br>*event:* The event source of the callback.<br>*checked:* The new checked state after the change.  You can pull out the new value by accessing `event.target.value` (string). You can pull out the new checked state by accessing `event.target.checked` (boolean). |
 | <span class="prop-name">required</span> | <span class="prop-type">bool</span> |  | If `true`, the `input` element will be required. |
 | <span class="prop-name">size</span> | <span class="prop-type">'medium'<br>&#124;&nbsp;'small'</span> | <span class="prop-default">'medium'</span> | The size of the switch. `small` is equivalent to the dense switch styling. |
 | <span class="prop-name">value</span> | <span class="prop-type">any</span> |  | The value of the component. The DOM API casts this to a string. The browser uses "on" as the default value. |

packages/material-ui/src/Switch/Switch.js

@@ -253,6 +253,8 @@ Switch.propTypes = {
    * Callback fired when the state is changed.
    *
    * @param {object} event The event source of the callback.
+   * @param {boolean} checked The new checked state after the change.
+   *
    * You can pull out the new value by accessing `event.target.value` (string).
    * You can pull out the new checked state by accessing `event.target.checked` (boolean).
    */