i18n: Add Japanese translations for r1s triggers

[niaka3dayo]

This PR adds Japanese translations to the existing R1S triggers. Please review and let me know if any adjustments are needed.

Changes

• Added Japanese translations for R1S Mouser
• Added Japanese translations for R1S Elevate and Eviscerate Launch Self
• Added Japanese translations for R1S Elevate and Eviscerate Launch Other
• Added Japanese translations for R1S Elevate and Eviscerate Stun Self
• Added Japanese translations for R1S Elevate and Eviscerate Stun Other
• Improved existing Japanese translation for R1S Splintering Nails to sound more natural

[MaikoTan]

Thanks for the rapid translation!