message: docs: use correct Nexclade cli flag for virus properties
diff: @@ -201,4 +201,4 @@ It is of the following schema (shortened for clarity):
  Nextclade Web (advanced mode): accepted in "Virus properties" drag & drop box.
  -Nextclade CLI flag: `--virus-properties`
  +Nextclade CLI flag: `--input-virus-properties`
  