fixes #3020, again: language_fallback enabled placeholder can screw things up
fixes #3020, again: language_fallback enabled placeholder can screw things up
added setup.cfg for wheel and version bump
Various documentation typo/spelling fixes

Most errors detected with Topy (https://github.com/intgr/topy), all
verified by hand.
Merge pull request #3037 from intgr/typo

Various documentation typo/spelling fixes
Merge pull request #3036 from benzkji/fix-3020

In edge cases, language_fallback in placeholder conf can make other plugins disappear.