doc-src/Tutorial/Datatype/tconstssubst

Added split_paired_All rule for splitting variables bound by
object-level universal quantifiers.

consts
   subst  :: ('a => ('a,'b)term) => ('a,'b)term      => ('a,'b)term
   substs :: ('a => ('a,'b)term) => ('a,'b)term list => ('a,'b)term list