Should a particle that is also a credential (`vd`, `mc`) count in a credential run after a comma?

[derek73]

#544 gave two rules the same question to answer, can this suffix word stand in a credential run?, and they answer it differently for the two words that are both particles and unambiguous suffix vocabulary, vd and mc.

• C1's run test (after a comma, _segment.py) counts them as suffix words.
• The anchor (_pieces._anchors) excludes them, because a particle chains onto the name after it (rules.md#P2). The anchor exclusion was added on PR fix(#544): a credential run keeps its ambiguous members #552 after Smith vd Ma, John lost the contiguity of its family name.

So the same words read differently depending on the path:

text	2.3.0	master	PR #552
John Smith, vd Ma	family John Smith vd Ma	family John Smith vd Ma	suffix vd Ma, reported
John Smith, PhD vd Ma	given PhD, middle Ma, suffix vd	given PhD, middle vd Ma	suffix PhD vd Ma, reported
Jan Smith PhD vd Ma	suffix PhD vd Ma	family vd Ma	family vd Ma
Doe, Jane PhD vd Ma	middle Ma, suffix PhD vd	middle vd Ma, silent	middle vd Ma, silent
John Smith, vd	suffix vd	suffix vd	suffix vd

(Mc reads the same way as vd.)

With a comma, vd Ma is a credential run; without one, the same two words are a family name. The last row shows why the comma reading isn't simply wrong: vd alone after a comma has always read as a suffix.

The question: after a comma, should a particle that is also a suffix word (a) count in the run, as today, so John Smith, vd Ma is a credential; or (b) end the run as it ends the anchor, so the part reads as the listing form?

(b) makes one predicate answer both questions: whether a word "has a live name reading" would decide both C1's run membership and the anchor. The cost is that John Smith, vd Ma returns to master's family John Smith vd Ma, a one-word listing-form part with no given name.

Aside: Doe, Jane PhD vd Ma puts vd Ma in middle without any report, on both master and #552. Whichever way this is decided, that silence deserves a look.