fix example block padding
fix example block padding

azuwis/asciidoctor-fopdf,getreu/asciidoctor-fopub,asciidoctor/asciidoctor-fopub,asciidoctor/asciidoctor-fopub,asciidoctor/asciidoctor-fopub,azuwis/asciidoctor-fopdf,getreu/asciidoctor-fopub,getreu/asciidoctor-fopub