NSMutableAttributedString Extensions

/// Adds an attribute with the given name and value to the entire receiver.
func addAttribute(_ name: NSAttributedString.Key, value: Any)
    
/// Removes the named attribute from the characters in the entire receiver.
func removeAttribute(_ name: NSAttributedString.Key)
    
/// Adds the characters of a given string to the end of the receiver.
func append(_ string: String)

/// Adds the given character to the end of the receiver.
func append(_ character: Character)