docs/ja_JP: translate submitting-patches.rst (interleaved-replies)

docs/ja_JP: translate submitting-patches.rst (interleaved-replies)

Translate the "Use trimmed interleaved replies in email discussions"
and "Don't get discouraged - or impatient" sections in
Documentation/translations/ja_JP/process/submitting-patches.rst.

Keep the wording close to the English text and wrap lines to match
the style used in the surrounding Japanese translation.

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: <20260606035954.27605-1-weibu@redadmin.org>