Update --quiet param description (#730)

Author: zcag

lib/i18n-js/cli/export_command.rb

@@ -30,7 +30,7 @@ class ExportCommand < Command
         opts.on(
           "-q",
           "--quiet",
-          "A Ruby file that must be loaded"
+          "Suppress non-error output"
         ) do |quiet|
           options[:quiet] = quiet
         end