chould you add `this` keyword example

Anyway, thank you for your guide.

how about add `this` keyword example

Dmitry Soshnikov's [ECMA-262-3 in detail](http://dmitrysoshnikov.com/ecmascript/chapter-3-this/#function-call-and-non-reference-type) talks `this` keyword in depth, but the version of specification he reference is ES3, and the url has outdated. So, could you add a secton to rewrite same topic in ES2018?
