* Add variant selectors for Greek lower Phi/Psi (`VXAG`, `VXAH`).
* Optimize cross position for Cyrillic Lower Straight U (`U+04AF`, `U+04B1`).
* Optimize glyph shape for `lower-gamma`.`straight` and `lower-gamma`.`curly`.
* Optimize glyph shape for `U+1DF15`.