Format verbs for parameter names fail to parse as HCL

[gdavison]

When a configuration contains a format verb as a parameter name, it is replaced with a quoted string, which fails HCL parsing.

For example, in https://github.com/hashicorp/terraform-provider-aws/blob/38319aa13aea65d3e946450c1f881d8fef12e734/aws/resource_aws_efs_file_system_test.go#L832-L836

resource "aws_efs_file_system" "test" {
  lifecycle_policy {
    %s = %q
  }
}

Expected Result

The line %s = %q should replace the leading bare string with something compatible with HCL parsing

Actual Result

The line %s = %q is replaced with "@@_@@ TFMT:%s:TFMT @@_@@" = "@@_@@ TFMT:%q:TFMT @@_@@", and terrafmt fmt fails