Added kh_key_idx_##name() helper function to encapsulate the repeated
pattern of calculating bucket index from key hash.
Replaced 2 instances of manual hash calculation:
- __hash_func(mrb,key) & khash_mask(h) → kh_key_idx_##name(mrb, key, h)
This eliminates the duplicated hash-and-mask pattern and makes the code
more readable by clearly expressing the intent (get bucket index for key).
Co-authored-by: Claude <noreply@anthropic.com>
Yukihiro "Matz" Matsumoto
7cfc863353