docs: ja_JP: process: translate first half of 'Describe your changes'

docs: ja_JP: process: translate first half of 'Describe your changes'

Translate the first half of the "Describe your changes" section in
Documentation/translations/ja_JP/process/submitting-patches.rst.

Replace "説明する" with "記述する" to match the distinction used in
ja_JP/process/howto.rst, and adjust line wrapping to ~74 columns.
Avoid cross-references for now by adding TODO notes to convert them to
file-local references when the destinations are translated.

Signed-off-by: Akiyoshi Kurita <weibu@redadmin.org>
Acked-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260225154706.5457-1-weibu@redadmin.org>