Error in change log

The first entry in the change log for v4.21.1:

> Completed implementation of support for [REML version 5](https://htmlpreview.github.io/?https://github.com/delphidabbler/codesnip/blob/version-4.21.0/Docs/Design/reml.html) (ommitted from v4.20.0 in error) and ...

has two errors:

1. It should refer to v4.21.0, not v4.20.0.
2. Spells omitted incorrectly.