docs: fix search bar only for iOS (#1295)

Fix searchBar only for iOS.

native-stack/README.md

@@ -357,12 +357,10 @@ Defaults to `auto`.
 
 Sets the translucency of the status bar (similar to the `StatusBar` component). Defaults to `false`.
 
-### Search bar (iOS only)
+### Search bar
 
 The search bar is just a `searchBar` property that can be specified in the navigator's `screenOptions` or an individual screen's `options`. Search bars are rarely static so normally it is controlled by passing an object to `searchBar` navigation option in the component's body.
 
-Search bar is only supported on iOS.
-
 Example: 
 
 ```js