adds documentation about text-decoration in role category (PR #1363) [skip ci]
adds documentation about text-decoration in role category (PR #1363) [skip ci]

After #1326 text-decoration was added and not documented
asciidoctor/asciidoctor-pdf,mojavelinux/asciidoctor-pdf,asciidoctor/asciidoctor-pdf,Hextremist/asciidoctor-pdf,Hextremist/asciidoctor-pdf,dsisnero/asciidoctor-pdf,mojavelinux/asciidoctor-pdf,dsisnero/asciidoctor-pdf