docs(accordion) added `md2-accordion-header` feature
docs(accordion) added `md2-accordion-header` feature

metaory/md2,mi9rom/md2,Promact/md2,metaory/md2,mi9rom/md2,Promact/md2,fcanocapdepon/md2,mi9rom/md2,fcanocapdepon/md2,metaory/md2,metaory/md2,Promact/md2,Promact/md2,fcanocapdepon/md2,mi9rom/md2,fcanocapdepon/md2