Fix TOML's new array of objects syntax

TOML recently added a syntax like:

```toml
[[servers]]
name = "alpha"
ip = "10.10.10.10"

[[servers]]
name = "beta"
ip = "20.20.20.20"
```

which compiles to

```js
[
  {
    name: "alpha",
    ip: "10.10.10.10"
  },
  {
    name: "beta",
    ip: "20.20.20.20"
  }
]
```

This change makes it syntax highlight correctly.