"Default" values for `FiniteStateMachine`s

[mkorbel1]

Motivation

Often there is a "default" value that would be desirable for most states in a FiniteStateMachine, but the current implementation requires repeating the same default across all states in order to avoid an inferred latch.

Desired solution

Upgrade the FiniteStateMachine API to support some way to add defaults.

This could easily be done by inserting conditional assignments (since they act as "blocking") before the rest of the combinational implementation in the Combinational that it generates.

Alternatives considered

No response

Additional details

No response