Use bool for boolean in w32menu.c, w32font.c, w32uniscribe.c.

Use bool for boolean in w32menu.c, w32font.c, w32uniscribe.c.

 src/w32uniscribe.c (uniscribe_list, uniscribe_match): Use bool where
 appropriate.
 src/w32font.c (struct font_callback_data, w32font_list_internal)
 (w32font_driver, w32font_match_internal): Use bool where appropriate.
 src/w32menu.c (x_activate_menubar, set_frame_menubar)
 (w32_dialog_show, initialize_frame_menubar, w32_menu_show)
 (is_simple_dialog): Use bool where appropriate.