Add clojure.math to magic require namespaces

[adrech]

Clojure 1.11.0 provides the new clojure.math namespace. Users will expect that it's magically required by "math", analog to the other builtins.

• [x] The commits are consistent with our contribution guidelines
• [ ] You've added tests (if possible) to cover your change(s)
• [x] The new code is not generating byte compile warnings (run cask exec emacs -batch -Q -L . -eval "(progn (setq byte-compile-error-on-warn t) (batch-byte-compile))" clj-refactor.el)
• [ ] All tests are passing (run ./run-tests.sh)
• [x] You've updated the changelog (if adding/changing user-visible functionality)
• [ ] You've updated the readme (if adding/changing user-visible functionality)

Thanks!