(U+81F3): Add `<-denotational@usage' for BUCS+81F3; apply new

(U+81F3): Add `<-denotational@usage' for BUCS+81F3; apply new
conventions for glyph granularity.
(U+5230): Add `<-denotational@usage' for BUCS+5230; apply new
conventions for glyph granularity.
(A-IWDSU+81F4): New abstract node.
(U+81F4): Add `<-denotational' for A-IWDSU+81F4; add
`<-denotational@usage' for BUCS+81F4 and BUCS+7DFB; apply new
conventions for glyph granularity.
(U-0002693A): Add `<-denotational' for A-IWDSU+81F4; apply new
conventions for glyph granularity.
(U+81F8): Apply new conventions for glyph granularity.
(U-0002C6F3): Likewise.
(U-00026941): Likewise.
(U+81FA): Add `<-denotational@usage' for BUCS+81FA and A2-DJT-09617;
modify structure.
(BUCS+81FA): New abstract node.
(BUCS+81F3): New abstract node; unify A2-DJT-09610.
(BUCS+81F4): New abstract node; unify A2-DJT-09611.
(A2-DJT-09617): New abstract node; use `<-denotational' for BUCS+81FA.