Return type for detailedDiff

[lucasprograms]

Update return type of detailedDiff to reflect the static top level properties:

Current:

export function detailedDiff (originalObj: object, updatedObj: object): object

Proposed:

type DetailedDiff = {
  added: object;
  deleted: object;
  updated: object;
};

export function detailedDiff (originalObj: object, updatedObj: object): DetailedDiff

[lucasprograms]

Closing as duplicate of #50