UnicodeScalar boundaries are: respected by: String.UTF8View.index(before:) on Swift 4 String.UTF16View.index(before:) on Swift 5 not respected by String.UTF16View.index(before:) on Swift 4 String.UTF8View.index(before:) on Swift 5UnicodeScalar boundaries are: respected by: String.UTF8View.index(before:) on Swift 4 String.UTF16View.index(before:) on Swift 5 not respected by String.UTF16View.index(before:) on Swift 4 String.UTF8View.index(before:) on Swift 5