* Variant names of certain letters are renamed, including:
- Upper Gamma (`grek-upper-gamma`).
- Variants for `K`, `k`, Cyrillic Ka (`К` and `к`).
* Add more serifed variants for `K`, `k`, `n`, Cyrillic Ka (`К` and `к`) and Cyrillic Ef (`ф`) to better reproduce PT Mono (#986).