Do not display a mark when files are auto-saved

This is kind of useless since users are not able to react to an
auto-save notification. It also causes all kinds of problems if the
status bar is in a non-standard mode (message, prompt, ...) and is prone
to race conditions if the status bar is updated by another thread at the
same time.

Signed-off-by: Lukas Fleischer <calcurse@cryptocrack.de>

src/calcurse.h

@@ -580,7 +580,6 @@ enum export_type {
 /* To customize the display when saving data. */
 enum save_display {
   IO_SAVE_DISPLAY_BAR,
-  IO_SAVE_DISPLAY_MARK,
   IO_SAVE_DISPLAY_NONE
 };