resolves #322 correctly calculate toc page range
resolves #322 correctly calculate toc page range

- range should be calculated relative to toc_page_number

mojavelinux/asciidoctor-pdf,asciidoctor/asciidoctor-pdf,dsisnero/asciidoctor-pdf,dsisnero/asciidoctor-pdf,asciidoctor/asciidoctor-pdf,mojavelinux/asciidoctor-pdf,Hextremist/asciidoctor-pdf,Hextremist/asciidoctor-pdf