Improve the usage for --help.

options.c

@@ -433,7 +433,7 @@ void usage(enum logcode F)
   rprintf(F," -4, --ipv4                  prefer IPv4\n");
   rprintf(F," -6, --ipv6                  prefer IPv6\n");
   rprintf(F,"     --version               print version number\n");
-  rprintf(F,"(-h) --help                  show this help (-h works with no other options)\n");
+  rprintf(F,"(-h) --help                  show this help (-h is --help only if used alone)\n");
 
   rprintf(F,"\n");
   rprintf(F,"Use \"rsync --daemon --help\" to see the daemon-mode command-line options.\n");