templatekw: have showlist() take mapping dict with no **kwargs expansion (API) See the previous commit for why. splitlines() does not pass a mapping dict, which would probably mean the legacy template didn't work from the beginning.

templatekw: change _showlist() to take mapping dict with no **kwargs expansion There was a risk that a template keyword could conflict with an argument name (e.g. 'name', 'values', 'plural', etc.) Let's make it less magical.

templatekw: rename 'args' to 'mapping' in showlist() The name 'args' provides no information. Call it 'mapping' as in templater.py.

templatekw: eliminate unnecessary temporary variable 'names' from _showlist() Replace 'names' with the optional argument 'plural'.

color: update the help with the new default The default is now "auto" we update the help to match reality.

upgrade: register all format variants in a list Now that all known format variants exists outside of the function, we can gather them in a lists. This build a single entry point other code can use (current target: extensions). The repository upgrade code is updated to simply use entries from this list. As a side effect this will also allow extensions to register their own format variants, to do this "properly" we should introduce a "registrar" for this category of object. However I prefer to keep this series simple, and that will be adventure for future time.