resolves #631 added square brackets around button in HTML output
resolves #631 added square brackets around button in HTML output

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