remove obsolete get_binding method
remove obsolete get_binding method

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