Use `shuowen-tongxundingsheng' instead of `shuowen-tongxun-dingsheng'

Use `shuowen-tongxundingsheng' instead of `shuowen-tongxun-dingsheng'
as a source ID.
(U+5927): Add `<-denotational@usage' for BUCS+5927; unify DJT-01946.
(U+593E): Add `<-denotational@usage' for BUCS+593E; apply new
conventions for glyph granularity.
(U+5950): Add `<-denotational@usage' for BUCS+5950.
(UU+5950): Unify DJT-01982.
(U-00021681): Add `<-denotational@usage' for BUCS+5F0A.
(BUCS+5927): New abstract node; unify A2-DJT-01946.
(BUCS+593E): New abstract node; unify A2-DJT-01966.
(BUCS+5950): Unify A2-DJT-01982.