* lisp/progmodes/bat-mode.el (bat-font-lock-keywords): Fontify argument numbers in %~n. Suggested by Jostein Kjønigsen <jostein@secure.kjonigsen.net> in emacs-devel. * test/lisp/progmodes/bat-mode-tests.el (bat-test-fontification-iter-var-1): Update the test to check also the %~n construct.