docs: ja_JP: SubmittingPatches: describe the 'Fixes:' tag

docs: ja_JP: SubmittingPatches: describe the 'Fixes:' tag

Sync the ja_JP translation with the following upstream commits:

commit 8401aa1f5997 ("Documentation/SubmittingPatches: describe the Fixes: tag")
commit 19c3fe285cba ("docs: Explicitly state that the 'Fixes:' tag shouldn't split lines")
commit 5b5bbb8cc51b ("docs: process: Add an example for creating a fixes tag")
commit 6356f18f09dc ("Align git commit ID abbreviation guidelines and checks")

The mix of plain text and reST markup for ``git bisect`` is intentional to
align with the eventual reST conversion.

Signed-off-by: Akiyoshi Kurita <weibu@redadmin.org>
Reviewed-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20250924192426.2743495-1-weibu@redadmin.org>