reason-react-native: add example for ScrollView scrollTo method (#577)

* reason-react-native: add example for ScrollView scrollTo method

* Update ScrollView.md

* Update ScrollView.md

* Update ScrollView.md

* Update ScrollView.md

Author: MoOx

reason-react-native/src/components/ScrollView.md

@@ -4,6 +4,67 @@ title: ScrollView
 wip: true
 ---
 
+## Methods
+
+### `scrollTo`
+
+Scrolls to a given `x`, `y` offset, either immediately, with a smooth animation, or,
+for Android only, a custom animation duration time.
+
+```reason
+let scrollParams = (~x: float, ~y: float, ~animated: bool=?, ~duration: float=?, unit) => unit;
+
+let scrollTo = (scrollView, scrollParams) => unit;
+```
+
+#### `scrollTo` Example
+
+```reason
+open ReactNative;
+
+[@react.component]
+let make = () => {
+  let scrollViewRef = React.useRef(Js.Nullable.null);
+  <ScrollView ref=scrollViewRef>
+    <TouchableOpacity
+      onPress={_ =>
+        switch (scrollViewRef->React.Ref.current->Js.Nullable.toOption) {
+        | Some(scrollView) =>
+          scrollView->ScrollView.scrollTo(
+            ScrollView.scrollToParams(~x=0., ~y=0., ~animated=true, ()),
+          )
+        | _ => ()
+        }
+      }>
+      <Text> "ScrollTo 0, 0"->React.string </Text>
+    </TouchableOpacity>
+  </ScrollView>;
+};
+```
+
+### `scrollToEnd`
+
+Scrolls to the end of the `ScrollView` with an animation.
+If this is a vertical `ScrollView` scrolls to the bottom.
+If this is a horizontal `ScrollView` scrolls to the right.
+
+```reason
+let scrollToEnd = (scrollView) => unit;
+```
+
+### `scrollToEndWithOptions`
+
+Similar to `scrollToEnd`, with options for animation or, for Android only duration.
+
+```reason
+let scrollToEndOptions = (~animated: bool=?, ~duration: float=?, unit) => unit;
+
+let scrollToEndWithOptions = (scrollView, scrollParams) => unit;
+```
+
+---
+
+
 ```reason
 include ScrollViewElement;