update the description of rerender

To be in line with testing-library/svelte-testing-library#210

Author: yanick

docs/svelte-testing-library/api.mdx

@@ -65,7 +65,7 @@ const view = render(YourComponent, {myProp: 'value'})
 | `component`  | The newly created Svelte component. Generally, this should only be used when testing exported functions, or when you're testing developer facing API's. Outside of said cases avoid using the component directly to build tests, instead of interacting with the rendered Svelte component, work with the DOM. Have a read of [Avoid the Test User](https://kentcdodds.com/blog/avoid-the-test-user) by Kent C. Dodds to understand the difference between the **end user** and **developer user**. |
 | `debug`      | Logs the `container` using [prettyDom](dom-testing-library/api-debugging.mdx/#prettydom).                                                                                                                                                                                                                                                                                                                                                                                                           |
 | `unmount`    | Unmounts the component from the `target` by calling `component.$destroy()`.                                                                                                                                                                                                                                                                                                                                                                                                                         |
-| `rerender`   | Calls render again destroying the old component, and mounting the new component on the original `target` with any new options passed in.                                                                                                                                                                                                                                                                                                                                                            |
+| `rerender`   | Calls [$set](https://svelte.dev/docs/client-side-component-api#$set) on the component. `rerender` takes in an option object just like `render`, but only the `props` key will be used.                                                                                                                                                                                                                                                                                                              |
 | `...queries` | Returns all [query functions](queries/about.mdx) that are bound to the `container`. If you pass in `query` arguments than this will be those, otherwise all.                                                                                                                                                                                                                                                                                                                                        |
 
 ## `cleanup`