add -F into short usage

src/optparse.c

@@ -46,9 +46,9 @@ static int usage(int e, char* prog_name)
 {
 	fprintf(stderr,
 #ifdef DEV_BUILD
-			"Usage: %s [-cCDhpPvVldsOLt]"
+			"Usage: %s [-cCDhpvVldsOLtfF]"
 #else
-			"Usage: %s [-cCDhpPvVldsOLf]"
+			"Usage: %s [-cCDhpvVldsOLfF]"
 #endif
 			" [-e boot arguments] [-k Pongo image] [-o overlay file] [-r ramdisk file] [-K KPF file]\n"
 			"Copyright (C) 2023, palera1n team, All Rights Reserved.\n\n"