* NEWS: Document this.
* spot/twa/twagraph.cc: `copy_state_names_from` handles this new info.
* spot/twaalgos/degen.hh, spot/twaalgos/degen.cc: Implement it.
* tests/python/origstate.py, tests/python/simstate.py: Update tests to
reflect the change.
* NEWS: Document the change.
* spot/twaalgos/simulation.cc: Implement the change.
* spot/twa/twagraph.cc: `copy_state_names_from` uses simulated states
info if present.
* spot/twaalgos/determinize.cc: Pretty-print in determinization follows
simulated states, avoiding possible confusion.
* tests/Makefile.am, tests/python/simstate.py: Add a test.
