[ja] Add -ntosuru form

[khaitruong922]

No description provided.

[khaitruong922]

んと為る is not used (only 10 results when searching exact match on Google) so let's not match this variant.

[codspeed-hq]

CodSpeed Performance Report

Merging #1393 will not alter performance

_{Comparing khaitruong922:ntosuru (f0cc220) with master (3f7832f)}

Summary

✅ 3 untouched benchmarks

🆕 2 new benchmarks
⁉️ 2 dropped benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	master	khaitruong922:ntosuru	Change
⁉️	japanese transformations (n=70)	20.8 ms	N/A	N/A
🆕	japanese transformations (n=72)	N/A	18.5 ms	N/A
⁉️	japanese transformations-full (n=193)	44.3 ms	N/A	N/A
🆕	japanese transformations-full (n=197)	N/A	45.5 ms	N/A

[Casheeew]

lgtm