getFontFace  
  ⚠️ Deprecated ⚠️
This is deprecated since version 4.10.
Use class@Gtk.FontDialog and class@Gtk.FontDialogButton instead
Gets the PangoFontFace representing the selected font group details (i.e. family, slant, weight, width, etc).
If the selected font is not installed, returns null.
Return
A PangoFontFace representing the selected font group details