improve return type for detailedDiff

Author: icholy

index.d.ts

@@ -6,4 +6,10 @@ export function deletedDiff (originalObj: object, updatedObj: object): object
 
 export function updatedDiff (originalObj: object, updatedObj: object): object
 
-export function detailedDiff (originalObj: object, updatedObj: object): object
+export interface DetailedDiff {
+    added: object
+    deleted: object
+    updated: object
+}
+
+export function detailedDiff (originalObj: object, updatedObj: object): DetailedDiff