Macro format_label 

macro_rules! format_label {
    ($data:ident, $($arg:tt)*) => { ... };
    ($data:ident : $data_ty:ty , $($arg:tt)*) => { ... };
    ($lit:literal $(, $arg:tt)*) => { ... };
}

Construct a Text widget using TextClass::Label which updates text using the format! macro

This is identical to format_text aside from the TextClass.