Changes from Mercurial (hg https://isabelle.in.tum.de/repos/isabelle/ default)
Summary
- tuned proof: avoid smt/z3 to make this work with arm64-linux;
- proper afp_directory (amending 9308bc5f65d6);
- clarified names;
- clarified name: avoid clash with Library.Update;
- clarified signature;
- tuned whitespace;
- clarified signature;