Ensures that attributes are fixed in the given range.
- iOS 7.0+
- macOS 10.0+
- tvOS 9.0+
The range of characters whose attributes might be examined.
NSText object using lazy attribute fixing is required to call this method before accessing any attributes within
range. This method gives attribute fixing a chance to occur if necessary.
NSText subclasses wishing to support laziness must call this method from all attribute accessors they implement.