Merge branch 'ma/asciidoctor-more-fixes'

Merge branch 'ma/asciidoctor-more-fixes'

Doc formatting updates.

* ma/asciidoctor-more-fixes:
  gitweb.conf.txt: switch pluses to backticks to help Asciidoctor
  git-merge-index.txt: wrap shell listing in "----"
  git-receive-pack.txt: wrap shell [script] listing in "----"
  git-ls-remote.txt: wrap shell listing in "----"
  Documentation: wrap config listings in "----"
  git-merge-base.txt: render indentations correctly under Asciidoctor
  Documentation: wrap blocks with "--"