Prompted by CVE-2021-3541, but this includes an awful lot of serious bug
fixes by Nick and others.
- configure.ac: bumped to new release
- doc/* updated and regenerated
* NEWS configure.in libxml.spec.in testapi.c doc/*: upated the news
regenerated the docs, preparing for release of 2.6.23
* pattern.c xmlschemas.c: fixed some comments
Daniel
* libxml.spec.in doc/devhelp/*: finished the integration with
devhelp, completing the index and inserted into the gtk-doc
database at "make install" stage
Daniel