scanner: Fix detection of zero-length heredoc anchor.
scanner: Fix detection of zero-length heredoc anchor.

hashicorp/hcl,hashicorp/hcl,strivecast/hcl,hashicorp/hcl,strivecast/hcl,hashicorp/hcl,hashicorp/hcl,strivecast/hcl,strivecast/hcl,strivecast/hcl