docs: update babel-loader example webpack config (#549)

Set mode to 'write-references' as recommended in readme

Author: MonkeyDo

examples/babel-loader/webpack.config.js

@@ -22,6 +22,7 @@ module.exports = {
           semantic: true,
           syntactic: true,
         },
+        mode: "write-references",
       },
     }),
   ],