Merge branch 'ja/doc-synopsis-style'

Doc mark-up fixes. * ja/doc-synopsis-style: doc: convert git-switch manpage to new synopsis style doc: convert git-mergetool options to new synopsis style doc: convert git-mergetool manpage to new synopsis style doc: switch merge config description to new synopsis format doc: convert merge strategies to synopsis format doc: merge-options.adoc remove a misleading double negation doc: convert merge options to new synopsis format doc: convert git-merge manpage to new style doc: convert git-checkout manpage to new style