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/parsers/smt2/smt2parser.cpp

@@ -3333,7 +3333,7 @@ namespace smt2 {
     };
 
     void free_parser(parser * p) { dealloc(p); }
-};
+}
 
 bool parse_smt2_commands(cmd_context & ctx, std::istream & is, bool interactive, params_ref const & ps, char const * filename) {
     smt2::parser p(ctx, is, interactive, ps, filename);

src/parsers/smt2/smt2scanner.cpp

@@ -403,5 +403,5 @@ namespace smt2 {
         m_bend = 0;
         next();
     }
-};
+}
 

src/parsers/smt2/smt2scanner.h

@@ -104,6 +104,6 @@ namespace smt2 {
         char const * cached_str(unsigned begin, unsigned end);
     };
 
-};
+}