Inclusive design: change whitelist to allowlist?

[lachlansimpson]

There are very few instances of the phrase whitelist in ansi_up.

They could be replaced relatively quickly and easily with allowlist.

https://developers.google.com/style/inclusive-documentation#replace

We would appreciate this change.

[drudru]

This would require an API change and force a new major release (semver).
If I do make a major change, I will replace the terms then.