cli: add a default range for object hash to cli help

Closes #1693.

Signed-off-by: Andrey Butusov <andrey@nspcc.io>

cmd/neofs-cli/modules/object/hash.go

@@ -42,7 +42,7 @@ func initObjectHashCmd() {
 	flags.String(commonflags.OIDFlag, "", commonflags.OIDFlagUsage)
 	_ = objectHashCmd.MarkFlagRequired(commonflags.OIDFlag)
 
-	flags.String("range", "", "Range to take hash from in the form offset1:length1,...")
+	flags.String("range", "", "Range to take hash from in the form offset1:length1,... Full object payload length if not specified")
 	flags.String("type", hashSha256, "Hash type. Either 'sha256' or 'tz'")
 	flags.String(getRangeHashSaltFlag, "", "Salt in hex format")
 }