doc: improve help message for the --validation option in dandi upload

Author: candleindark

dandi/cli/cmd_upload.py

@@ -39,7 +39,8 @@
 )
 @click.option(
     "--validation",
-    help="Data must pass validation before the upload.  Use of this option is highly discouraged.",
+    help="Data must pass validation before the upload. "
+    "Not requiring validation is highly discouraged.",
     type=click.Choice(list(UploadValidation)),
     default="require",
     show_default=True,