[ja] add ~ておく conjugation

[khaitruong922]

• Add -teoku conjugation (similar to -teiru works)
• Remove -toku conjugation and move its rules to -teoku.
• Add ないでおく, ないどく

[codspeed-hq]

CodSpeed Performance Report

Merging #1399 will not alter performance

_{Comparing khaitruong922:teoku (2a30118) with master (aaa1617)}

Summary

✅ 3 untouched benchmarks

🆕 2 new benchmarks
⁉️ 2 (👁 2) dropped benchmarks

Benchmarks breakdown

	Benchmark	master	khaitruong922:teoku	Change
👁	japanese transformations (n=72)	18.5 ms	N/A	N/A
🆕	japanese transformations (n=76)	N/A	23 ms	N/A
👁	japanese transformations-full (n=197)	45.5 ms	N/A	N/A
🆕	japanese transformations-full (n=207)	N/A	48.3 ms	N/A