Fix README browserify explanation

README.md

@@ -71,7 +71,7 @@ This is because of the function-name-duck-typing used in [typeforce](https://git
 
 Example:
 ``` bash
-uglifyjs ... --mangle --reserved 'BigInteger,ECPair,Point'
+uglifyjs ... --mangle reserved=['BigInteger','ECPair','Point']
 ```
 
 **NOTE**: This library tracks Node LTS features,  if you need strict ES5,  use [`--transform babelify`](https://github.com/babel/babelify) in conjunction with your `browserify` step (using an [`es2015`](http://babeljs.io/docs/plugins/preset-es2015/) preset).