syntax highlighting: vue.js single-file components

Created by: bobheadxi

• Sourcegraph version: sourcegraph.com
• Platform information: sourcegraph.com

Steps to reproduce:

1. open a VueJS single-file component: https://sourcegraph.com/github.com/ubclaunchpad/ubclaunchpad.com/-/blob/src/components/Button.vue

Expected behavior:

Syntax highlighting like in VS code (driven by Vetur (language server)):

Actual behavior: