newWithMnemonic
Creates a new GtkButton containing a label.
If characters in @label are preceded by an underscore, they are underlined. If you need a literal underscore character in a label, use “__” (two underscores). The first underlined character represents a keyboard accelerator called a mnemonic. Pressing Alt and that key activates the button.
Return
a new GtkButton
Parameters
label
The text of the button, with an underscore in front of the mnemonic character