i18n-ja: synchronized with 838025b15925

--HG--
branch : stable
help: always show command help with -h (issue4240)

Old behavior:
              hg help x    hg x -h    hg help -e x  hg help -c x
config        topic        topic (!)  -             cmd
showconfig    cmd          topic (!)  -             cmd
rebase        cmd          cmd        ext           cmd

New behavior:
              hg help x    hg x -h    hg help -e x  hg help -c x
config        topic        cmd        -             cmd
showconfig    cmd          cmd        -             cmd
rebase        cmd          cmd        ext           cmd

--HG--
branch : stable
extra : amend_source : dd015e46ea327fc24f3be96961524afe9945f92e
merge with i18n

--HG--
branch : stable