cp: trim help text

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

coreutils/cp.c

@@ -16,9 +16,9 @@
  */
 
 //usage:#define cp_trivial_usage
-//usage:       "[OPTIONS] SOURCE DEST"
+//usage:       "[OPTIONS] SOURCE... DEST"
 //usage:#define cp_full_usage "\n\n"
-//usage:       "Copy SOURCE to DEST, or multiple SOURCE(s) to DIRECTORY\n"
+//usage:       "Copy SOURCE(s) to DEST\n"
 //usage:     "\n	-a	Same as -dpR"
 //usage:	IF_SELINUX(
 //usage:     "\n	-c	Preserve security context"