docs: Updated crypt/cryptdecode docs with additional info

cmd/cryptdecode/cryptdecode.go

@@ -36,6 +36,9 @@ use it like this
 	rclone cryptdecode encryptedremote: encryptedfilename1 encryptedfilename2
 
 	rclone cryptdecode --reverse encryptedremote: filename1 filename2
+
+Another way to accomplish this is by using the ` + "`rclone backend encode` (or `decode`)" + `command.
+See the documentation on the ` + "`crypt`" +  ` overlay for more info.
 `,
 	Run: func(command *cobra.Command, args []string) {
 		cmd.CheckArgs(2, 11, command, args)

docs/content/crypt.md

@@ -557,3 +557,7 @@ then rclone uses an internal one.
 `scrypt` makes it impractical to mount a dictionary attack on rclone
 encrypted data.  For full protection against this you should always use
 a salt.
+
+## SEE ALSO
+
+* [rclone cryptdecode](/commands/rclone_cryptdecode/)    - Show forward/reverse mapping of encrypted filenames