[ja] add volitional slang

[khaitruong922]

行こうかー＞行こっか
行きましょうかー＞行きましょっか

[codspeed-hq]

CodSpeed Performance Report

Merging #1397 will not alter performance

_{Comparing khaitruong922:volitional-slang-2 (d9ca981) with master (aaa1617)}

Summary

✅ 3 untouched benchmarks

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

Benchmarks breakdown

	Benchmark	master	khaitruong922:volitional-slang-2	Change
👁	japanese transformations (n=72)	18.5 ms	N/A	N/A
🆕	japanese transformations (n=74)	N/A	18.9 ms	N/A
👁	japanese transformations-full (n=197)	45.5 ms	N/A	N/A
🆕	japanese transformations-full (n=203)	N/A	46.8 ms	N/A