Change rsync help for -a to show that it is equivalent to -rlptgoD.

I've had to go to the man page many times for that information and I
finally got sick of it.

options.c

@@ -211,7 +211,7 @@ void usage(enum logcode F)
   rprintf(F," -v, --verbose               increase verbosity\n");
   rprintf(F," -q, --quiet                 decrease verbosity\n");
   rprintf(F," -c, --checksum              always checksum\n");
-  rprintf(F," -a, --archive               archive mode\n");
+  rprintf(F," -a, --archive               archive mode, equivalent to -rlptgoD\n");
   rprintf(F," -r, --recursive             recurse into directories\n");
   rprintf(F," -R, --relative              use relative path names\n");
   rprintf(F," -b, --backup                make backups (default %s suffix)\n",BACKUP_SUFFIX);

rsync.yo

@@ -285,7 +285,7 @@ verb(
  -v, --verbose               increase verbosity
  -q, --quiet                 decrease verbosity
  -c, --checksum              always checksum
- -a, --archive               archive mode
+ -a, --archive               archive mode, equivalent to -rlptgoD
  -r, --recursive             recurse into directories
  -R, --relative              use relative path names
  -b, --backup                make backups (default ~ suffix)