(IWDS1-0020): Add `<-denotational@component' for IWDS1-020+021 and

(IWDS1-0020): Add `<-denotational@component' for IWDS1-020+021 and
A-compU+722B.
(IWDS1-020+021): New abstract node; unify A-BC-8A73.
(BC-88F0): Separate GT-K00758 and IWDS1-0020; use IWDS1-0020 instead
of IWDS1-0021 and A-compU+722B as the target of
`<-denotational@component'.
(BC-8C4F): Use IWDS1-0020 instead of BC-88F0 in
`ideographic-structure'; apply new conventions for glyph granularity.