(U+529F): Add `<-denotational@usage' for BUCS+529F; apply new

(U+529F): Add `<-denotational@usage' for BUCS+529F; apply new
conventions for glyph granularity.
(U+52B9): Add `<-denotational@usage' for A2-DJT-00872 and BUCS+6548;
apply new conventions for glyph granularity.
(U+52E3): Add `<-denotational@usage' for BUCS+52E3; apply new
conventions for glyph granularity.
(U+52E6): Use `<-denotational@usage' instead of `<-denotational' for
BUCS+527F; add ideographic-structure.
(UU+52E6): Unify DJT-00902.
(BUCS+529F): Unify A2-DJT-00857.
(BUCS+52E3): New abstract node; unify A2-DJT-00899.
(A2-DJT-00872): New abstract node; use `<-denotational' BUCS+6548.