(C6-2251): Unify U-00020ADA instead of A-IWDSU+20ADA and IU+20ADA; use

(C6-2251): Unify U-00020ADA instead of A-IWDSU+20ADA and IU+20ADA; use
A-cgnU+20ADA instead of U-00020ADA as its mother; add
`<-denotational@usage' for BUCS+725F.
(A-cgnU+20ADA): Changed from U-00020ADA; use `<-denotational@usage'
instead of `<-denotational' for BUCS+725F.
(HNG-KHI0106-0): Use A-cgnU+20ADA instead of U-00020ADA as its mother;
add `<-denotational@usage' for BUCS+725F; modify component.
(HNG-KHM0088-0): Use `<-denotational@usage' instead of
`<-denotational' for BUCS+725F; add `<-denotational' for A-cgnU+20ADA.