Improve refences to non-Latin letters

[danshil]

The original article speaks of cyrillic [sic] letters and hieroglyphs, but uses Cyrillic letters and Hanzi as its example. Changes create consistency between variables and reference terminology.

[CLAassistant]

All committers have signed the CLA.

[joaquinelio]

Uppercase Cyrillic

[joaquinelio]

use Cyrillic letters odd, I know. It seems like an adjective, but from Grammarly com: My mother is British, and my father is Dutch.