add template for admonition block; use attr method
add template for admonition block; use attr method

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