Use `->subsumptive' for some character definitions.

Use `->subsumptive' for some character definitions.
(M-42712): Unify U-0002925C.
(U+976C): Unify JC3-8DBD.
(U+9773): Unify JC3-6CC1.
(J90-3724): Unify JC3-6CCB.
(U+9776): Unify JC3-8BF4.
(J90-3373): Unify JC3-6CCA.
(G0-474A): Unify JC3-6CCC.
(M-42896): Unify CB02709.
(M-42899): Unify U-000292D7.
(JSP-674A): Unify JC3-6CC2; separate C3-567B; moved into U+979F.
(U+979F): Use `->subsumptive'.
(U+97AE): Unify JC3-6CC3.
(C5-5F64): Map to M-42945.
(JSP-674E): Unify JC3-6CC4.
(JSP-6752): Unify JC3-6CC5.
(U+97BC): Unify JC3-6CC6.
(M-43036): Unify JC3-6CC7.
(U+97C1): Unify JC3-6CC8.
(GT-57774): Unify JC3-6CC9.