[$] New features and other changes in Python3.10

Python 3.10 is proceeding apace; everything looks to be ontrack for the final release, which is expected onOctober 4. The beta releases started in early May, with the first of those marking the feature-freeze for this version ofthe language. There are a number of interesting changes that are coming withPython 3.10, including what is perhaps the "headline feature":structural pattern matching.