Parses str which is marked up with the Pango text markup language,
setting the label's text and attribute list based on the parse results.
If characters in str are preceded by an underscore, they are underlined
indicating that they represent a keyboard accelerator called a mnemonic.
The mnemonic key can be used to activate another widget, chosen
automatically, or explicitly using gtk_label_set_mnemonic_widget().
Parses str which is marked up with the Pango text markup language, setting the label's text and attribute list based on the parse results. If characters in str are preceded by an underscore, they are underlined indicating that they represent a keyboard accelerator called a mnemonic. The mnemonic key can be used to activate another widget, chosen automatically, or explicitly using gtk_label_set_mnemonic_widget().