Creates a new GtkLabel, containing the text in @str.
If characters in @str 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. The mnemonic key can be used
to activate another widget, chosen automatically, or explicitly using
[method@Gtk.Label.set_mnemonic_widget].
If [method@Gtk.Label.set_mnemonic_widget] is not called, then the first
activatable ancestor of the GtkLabel will be chosen as the mnemonic
widget. For instance, if the label is inside a button or menu item,
the button or menu item will automatically become the mnemonic widget
and be activated by the mnemonic.
Creates a new GtkLabel, containing the text in @str.
If characters in @str 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. The mnemonic key can be used to activate another widget, chosen automatically, or explicitly using [method@Gtk.Label.set_mnemonic_widget].
If [method@Gtk.Label.set_mnemonic_widget] is not called, then the first activatable ancestor of the GtkLabel will be chosen as the mnemonic widget. For instance, if the label is inside a button or menu item, the button or menu item will automatically become the mnemonic widget and be activated by the mnemonic.