Merge branch 'js/subtree-doc-update-to-asciidoctor-2'

Doc markup update. * js/subtree-doc-update-to-asciidoctor-2: subtree: fix build with AsciiDoctor 2

Junio C Hamano committed Apr 28, 2020 at 15:50 UTC 772d78563697c39d5d35d090cb2b5724a1812e7f

No changes.