Merge branch 'bc/asciidoctor-tab-width'

Asciidoctor gives a reasonable imitation for AsciiDoc, but does not render illustration in a literal block correctly when indented with HT by default. The problem is fixed by forcing 8-space tabs. * bc/asciidoctor-tab-width: Documentation: render revisions correctly under Asciidoctor Documentation: use 8-space tabs with Asciidoctor