fix(guide): remove redundant hint (#2188)

fix(guide): remove redundant hint (#2188)

Author: gish

src/content/guides/tree-shaking.md

@@ -9,6 +9,7 @@ contributors:
   - MijaelWatts
   - dmitriid
   - probablyup
+  - gish
 related:
   - title: "webpack 4 beta — try it today!"
     url: https://medium.com/webpack/webpack-4-beta-try-it-today-6b1d27d7d7e2#9a67
@@ -172,8 +173,6 @@ module.exports = {
 };
 ```
 
-T> Note that the `--optimize-minimize` flag can be used to insert the `UglifyJSPlugin` as well.
-
 With that squared away, we can run another `npm run build` and see if anything has changed.
 
 Notice anything different about `dist/bundle.js`? Clearly the whole bundle is now minified and mangled, but, if you look carefully, you won't see the `square` function included but will see a mangled version of the `cube` function (`function r(e){return e*e*e}n.a=r`). With minification and tree shaking our bundle is now a few bytes smaller! While that may not seem like much in this contrived example, tree shaking can yield a significant decrease in bundle size when working on larger applications with complex dependency trees.