Removed (now unneeded) declarations of realizers for induction on lists and letters.
Removed (now unneeded) declarations of realizers for induction on lists and letters.

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle