fix: enhance scrollTo ts type (#91)

Co-authored-by: afc163 <[email protected]>

Author: nuintun

src/List.tsx

@@ -37,7 +37,7 @@ export interface ScrollInfo {
 
 export type ScrollConfig = ScrollTarget | ScrollPos;
 
-export type ScrollTo = (arg: number | ScrollConfig) => void;
+export type ScrollTo = (arg?: number | ScrollConfig | null) => void;
 
 export type ListRef = {
   nativeElement: HTMLDivElement;