Returns a new string containing the characters of the receiver from the one at a given index to the end.
- iOS 2.0+
- macOS 10.0+
- tvOS 9.0+
- watchOS 2.0+
An index. The value must lie within the bounds of the receiver, or be equal to the length of the receiver.
an- 1) lies beyond the end of the receiver.
A new string containing the characters of the receiver from the one at
an to the end. If
an is equal to the length of the string, returns an empty string.