Clarify a 'chil' engine param that is a little unintuitive.

Submitted by: Sander Temme <sander@temme.net>

engines/e_chil.c

@@ -164,11 +164,11 @@ static const ENGINE_CMD_DEFN hwcrhk_cmd_defns[] = {
 		ENGINE_CMD_FLAG_STRING},
 	{HWCRHK_CMD_FORK_CHECK,
 		"FORK_CHECK",
-		"Turns fork() checking on or off (boolean)",
+		"Turns fork() checking on (non-zero) or off (zero)",
 		ENGINE_CMD_FLAG_NUMERIC},
 	{HWCRHK_CMD_THREAD_LOCKING,
 		"THREAD_LOCKING",
-		"Turns thread-safe locking on or off (boolean)",
+		"Turns thread-safe locking on (zero) or off (non-zero)",
 		ENGINE_CMD_FLAG_NUMERIC},
 	{HWCRHK_CMD_SET_USER_INTERFACE,
 		"SET_USER_INTERFACE",