wrap more specific messages inside ErrIllegalAction

[todo]

riverboat/errors.go

Lines 30 to 35 in ff3b892

	//TODO: wrap more specific messages inside ErrIllegalAction
	// ErrIllegalAction is returned when an Action is valid (all parameters are well-formed), but
	// it is illegal per the laws of poker given the state of the game at that time. This could include
	// illegal bet amounts, out-of-turn plays, or other violations of the rules.
	var ErrIllegalAction = errors.New("this action cannot be performed at this time")

---

This issue was generated by todo based on a TODO comment in ff3b892. It's been assigned to @alexclewontin because they committed the code.