Wrong highlighting for function that splits over multiple lines inside a string

[dbanck]

Originally reported in hashicorp/vscode-terraform#1756

Example

locals {
  list = [
    "1", "2", "3"
  ]
  function = [
    for i in local.list : "Out: ${join("-", [i, "join"]
    )}" if i != "2"
  ]
}

output "test" {
  value = local.function
}

It breaks some time after the 0.4.2 release