chore: update .api.md for react-positioning

Author: robertpenner

packages/react-components/react-positioning/library/etc/react-positioning.api.md

@@ -43,7 +43,7 @@ export function getSlideOffsets(options: GetSlideOffsetsOptions): SlideOffsets;
 
 // @public
 export type GetSlideOffsetsOptions = {
-    placement: PositioningPlacement;
+    placement: PositioningPlacement | null;
     distance: string;
 };