feat(reducer/combineActionHandlers): perf for n=1 & common errors
feat(reducer/combineActionHandlers): perf for n=1 & common errors

Warnings when:

- no handlers defined
- there is an handler for the action type `type` (likely an error)

There is now an optimized implementation when there is only one handler.

lmcro/xo-web,vatesfr/xo-web,lmcro/xo-web,lmcro/xo-web,vatesfr/xo-web