Field feature_names contains a null-terminated sorted array of feature
names. Bitmask field features is deprecated.
Documentation is updated. Test 1177 and tests/version-scan.pl updated to
match new documentation format and extended to check feature names too.
Closes#9583
Add licensing and copyright information for all files in this repository. This
either happens in the file itself as a comment header or in the file
`.reuse/dep5`.
This commit also adds a Github workflow to check pull requests and adapts
copyright.pl to the changes.
Closes#8869
