Add soft keywords to rlcompleter

Let the interpreter autocomplete [soft-keywords](https://docs.python.org/dev/reference/lexical_analysis.html#soft-keywords), ATM the [PEP-634](https://peps.python.org/pep-0634/) _match / case / \_(wildcard pattern)_.