GroovyDoc generates CLASS_NAME.1.html if an enum class has an abstract method

I found that the GroovyDoc generates `CLASS_NAME.1.html` if an enum class has an abstract method. I found this in the spotbugs-gradle-plugin project, and I've created a MCVE project at GitHub. The code to reproduce will be like below:

enum TestWithAbstractMethod {
    FOO {
        int method() { return 0; }
    },
    BAR {
        int method() { return 1; }
    }
    abstract int method();
}

You can find generated HTML files in this GitHub Actions Workflow Run. It includes not TestWithAbstractMethod.html but TestWithAbstractMethod*.1*.html.

The build log contains no meaningful warning. I've confirmed that GroovyDoc 3.0.2 also reproduces this issue, so I guess that the change between v2 and v3 introduce this unexpected behavior.