japanese/p5-Lingua-*: fix duplicate p5-p5- PKGNAMEPREFIX

japanese/p5-Lingua-JA-Moji had duplicate p5-p5- prefix and
japanese/p5-Lingua-JA-Numbers didn't have ja- prefix.
Set ja-p5- prefix to all Lingua ports under Japanese category.

PR: 229184
Submitted by: Tomohiro Hosaka <bokutin@bokut.in> (initial version)
Reviewed by: pi, mat
Approved by: pi (mentor)
Differential Revision: https://reviews.freebsd.org/D16002