Make sure include the path to the js file not css (#7947)
Make sure include the path to the js file not css (#7947)

* Make sure include the path to the js file not css

It'd be ideal to prefetch the css files as well but we'll skip that for
now as there's generally relatively few css chunks and they'll get
loaded when we hover on a link, etc.

I'll create an issue about adding support for it.

* Just check if it's a .js file directly

mingaldrichgan/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,mingaldrichgan/gatsby,mingaldrichgan/gatsby,0x80/gatsby,ChristopherBiscardi/gatsby,ChristopherBiscardi/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,0x80/gatsby,gatsbyjs/gatsby,gatsbyjs/gatsby,0x80/gatsby,ChristopherBiscardi/gatsby,ChristopherBiscardi/gatsby