internal declared on an Event has no effect at trigger time

[fgmacedo]

Event(a.to(b), internal=True) is meant to put the event on the internal queue, which is what
Event.put reads (self._sm._put_nonblocking(trigger_data, internal=self.internal)). But nothing
ever carries the declared value to the object that put is called on:

• Event.__get__ builds BoundEvent(id=..., name=..., delay=..., _sm=instance) and omits
  internal, so sm.go() always uses the default False.
• StateChart.send reads know_event.delay from the class attribute but takes internal only
  as its own parameter, so sm.send("go") ignores the declaration too.

Measured after #645, which fixed the declaration side:

class Internal(StateChart):
    a = State(initial=True)
    b = State(final=True)
    go = Event(a.to(b), internal=True)

[e.internal for e in Internal.events]  # [True]  -- declaration is preserved
Internal().go.internal                 # False   -- the bound event is not

delay works end to end through both paths; internal is the one left inert. #645 fixed the declaration side (see #647, closed) and deliberately stopped there, because the
remaining fix lives in event.py and statemachine.py, outside what that PR touched.

When fixing: docs/releases/3.2.2.md currently states that internal is preserved on the
declaration; update that once it actually takes effect, check whether docs/processing_model.md
should show the declarative form next to raise_(), and add an entry to the open release notes.