Spelling (was: Correction of typo in documentation of KEY_CONSIDERED)

[Vincent Breitmoser]

> Typos in source code comments are not relevant for the users and development
> is done on master were rarely done typo and grammar fixes for comments are
> acceptable.

I understand the feeling that these things are ultimately unimportant. But the
long term effect of this attitude is certainly noticeable in the codebase:

https://fossies.org/linux/misc/gnupg-2.2.20.tar.bz2/codespell.html

 - V