resolves #756, upgrade to highlight.js 7.4
resolves #756, upgrade to highlight.js 7.4

asciidocfx/asciidoctor,anthonny/asciidoctor,yukisan/asciidoctor,pepijnve/asciidoctor,gjtorikian/asciidoctor,neontapir/asciidoctor,neontapir/asciidoctor,glamouracademy/asciidoctor,cuit-zhaxin/asciidoctor,benignbala/asciidoctor,yukisan/asciidoctor,cuit-zhaxin/asciidoctor,pepijnve/asciidoctor,mjang/mj-asciidoc,gjtorikian/asciidoctor,mjang/mj-asciidoc,anthonny/asciidoctor,glamouracademy/asciidoctor,benignbala/asciidoctor,asciidocfx/asciidoctor