packager: Resolver/polyfills/require: fix nit error message

Reviewed By: davidaurelio

Differential Revision: D4713066

fbshipit-source-id: 35f09ded85472191a3f1c36b5879acee55c60b8b

packager/src/Resolver/polyfills/require.js

@@ -195,7 +195,8 @@
    let message = 'Requiring unknown module "' + id + '".';
    if (__DEV__) {
      message +=
-      'If you are sure the module is there, try restarting the packager or running "npm install".';
+      'If you are sure the module is there, try restarting the packager. ' +
+      'You may also want to run `npm install`, or `yarn` (depending on your environment).';
    }
    return Error(message);
  }