Romancal steps and suffix treatment

[braingram]

In many locations in the romancal code Step.suffix is set to a seemingly default value for a respective step:
https://github.com/search?q=repo%3Aspacetelescope%2Fromancal%20%22suffix%20%3D%22&type=code

To consider one example, AssignWcsStep sets it's suffix as follows:

romancal/romancal/assign_wcs/assign_wcs_step.py

Lines 48 to 52 in d837289

	if self.save_results:
	try:
	self.suffix = "assignwcs"
	except AttributeError:
	self["suffix"] = "assignwcs"

To allow files generated by the step (when save_results=True, when the suffix is used) to have the assignwcs suffix.

This could alternatively be handled by setting the suffix in the spec (as is done for several steps in jwst). This has a few benefits:

• it provides automatic documentation of the expected suffix (see one example in jwst)
• it is configurable by the user (who can override the suffix via strun options, config files, etc)
• it does not require the try/except and other code above

Was this a design decision to not use the spec to define the suffix or is using the spec ok?