Remove unnecessary semicolons (Attempt 2) (#10020)

This is another PR towards the goal of getting Z3 to compile cleanly
when included via FetchContents into clang-tidy, which uses a pretty
strict set of warnings.

This is a second version of https://github.com/Z3Prover/z3/pull/9957. I
address @NikolajBjorner 's comments about not changing the semicolons
after macro invocations, because some editors work better with them
present. It now, to the best of my ability, only deletes semis:

* after the closing brace of namespace decl.
* after the closing brace of an extern "C" decl.
* after a function definition.

This PR is very large, but it consists entirely of deletions of
semicolons in these situations.

(If there was a way to update the previous PR, which had been closed,
and that is preferable, please let me know. I couldn't figure it out.)

src/math/grobner/pdd_simplifier.cpp

@@ -494,7 +494,7 @@ namespace dd {
                 hash(unsigned_vector& vars):vars(vars) {}
                 bool operator()(mon const& m) const {
                     return unsigned_ptr_hash(vars.data() + m.offset, m.sz, 1);
-                };
+                }
             };
             struct eq {
                 unsigned_vector& vars;