fix: code

Author: alexander-akait

bin/cli-flags.js

@@ -230,7 +230,7 @@ module.exports = {
     },
     {
       name: 'watch-files',
-      type: [String],
+      type: String,
       configs: [
         {
           type: 'string',

lib/options.json

@@ -502,7 +502,7 @@
       "setupExitSignals": "should be {Boolean} (https://webpack.js.org/configuration/dev-server/#devserversetupexitsignals)",
       "static": "should be {Boolean|String|Object|Array} (https://webpack.js.org/configuration/dev-server/#devserverstatic)",
       "transportMode": "should be {String|Object} (https://webpack.js.org/configuration/dev-server/#devservertransportmode)",
-      "watchFiles": "should be {String|Array} (https://webpack.js.org/configuration/dev-server/#devserverwatchfiles)"
+      "watchFiles": "should be {String|Array|Object} (https://webpack.js.org/configuration/dev-server/#devserverwatchfiles)"
     }
   },
   "additionalProperties": false