Merge branch 'ja/doc-markup-updates'

Documentation rules has been explicitly described how to mark-up
literal parts and a few manual pages have been updated as examples.

* ja/doc-markup-updates:
  doc: git-clone: do not autoreference the manpage in itself
  doc: git-clone: apply new documentation formatting guidelines
  doc: git-init: apply new documentation formatting guidelines
  doc: allow literal and emphasis format in doc vs help tests
  doc: rework CodingGuidelines with new formatting rules