intelisense won't work for require with template strings

_From @NikosEfthias on April 14, 2016 19:9_
- VSCode Version:1.8.2
- OS Version:ubuntu 15.10

Steps to Reproduce:

``` javascript
const a=require("something") //autocomplete works great
const b=require('something') //autocomplete works great
const c=require(`something`) //will not autocomplete
```

_Copied from original issue: Microsoft/vscode#5273_
