Adds a code for getting character width togeter with LUTs generated
using uni2characterwidth from Unicode 11 lists.
Skin tone, flags, gender, and other emoji with and modifer are not
joined (you will see e.g. a skin tone square + generic yellow emoji).
I think joining them would cause problems in most editors, command line
prompts, and other programs which use character width data, as the
characters would behave as combining or emoji depending on context (like
- light thumb up: 👍🏻
- dark thumb up: 👍🏿
- Polish flag: 🇵🇱
This behavior is allowed:
It is possible to add support for sequences, but those would work
only for a string width functions.
Some characters which can be presented as emoji are narrow (e.g. ✖️, ©️).
Those characters are listed without "presentation" mode, which means
they should be rendered as text by default (real presentation depends on
renderer and/or font). Noto Sans Color Emoji renders them as wide,
DejaVu Sans as narrow. Vim, bash and zsh treat them as narrow, so I made
Depends on D15757