Sets the button title to the specified attributed string.
- watchOS 2.0+
The formatted text string to be displayed in the button. Specifying
nilclears the current text from the button.
This method sets the content of the button to the specified text, replacing the previous text. The text is drawn using the style information in
attributed. If the button has a background image, the text is drawn on top of that image.
If you use styled text in your buttons, you must provide localized versions of the text yourself. Attributed strings may not contain any NSTextAttachment objects as part of their content.