ieee: mirror the C2 regroup; the urn parser reads the YYYY-MM tail

[ronaldtse]

ieee: mirror the C2 regroup; the urn parser reads the YYYY-MM tail

Mirrors the gem's C2 regroup (pubid#504/#505/#506, corpus
testsuite@c4ce2d5):

• a draft type word never reaches the wire ("Standard" folds to
  "Std"; Draft-typed spellings are dropped before the attribute -
  still feeding the stage lookup for the version-less D1 fabrication)
• the render prints the word Draft alone for a status-less draft
• a base year dash-attaches to the code when the draft holds its own
  date (the draft+corrigendum family)
• a year-only draft date keeps its comma form ("ANSI N42.34/D9a,
  2015")
• the ieee urn parser splits a -YYYY-MM tail into year + numeric
  month, so dated references render like the reference ("21, 11
  1976"); three urn-parity rows re-pinned to the gem's current
  renders

The pend ledger re-derives at the new corpus: 435 ieee rows - the
dated-draft render surface this port has not reproduced yet (forced-
comma forms, D= designator faces, the year-only compose) - plus the
unchanged nist 48 (#498's section/indx/translation renders) and itu

1. TESTSUITE_REF -> c4ce2d5; artifact rebuilt (42 flavors, 99,666
   cases).