website: fix headings

website/src/docs/stores.md

@@ -63,12 +63,12 @@ const uppy = Uppy({
 })
 ```
 
-### `opts.store`
+#### `opts.store`
 
 Pass a Redux store instance, from `Redux.createStore`.
 This instance should have the Uppy reducer mounted somewhere already.
 
-### `opts.id`
+#### `opts.id`
 
 By default, the `ReduxStore` assumes Uppy state is stored on a `state.uppy[id]` key.
 `id` is randomly generated by the store constructor, but can be specified by passing an `id` option if it should be predictable.
@@ -80,7 +80,7 @@ ReduxStore({
 })
 ```
 
-### `opts.selector`
+#### `opts.selector`
 
 If you'd rather not store the Uppy state under the `state.uppy` key at all, use the `selector` option to the `ReduxStore` constructor to tell it where to find state instead: