gnu: emacs: Fix ert-runner by adding 'reporters' subdirectory.

Previous this change, ert-runner would fail with error:
"Invalid reporter: dot".

* gnu/packages/emacs.scm (ert-runner)[include]: Add regexp to match elisp
files under the 'reporters' subdirectory.

Signed-off-by: Arun Isaac <arunisaac@systemreboot.net>

gnu/packages/emacs.scm

@@ -4814,7 +4814,8 @@ Emacs.")
                           ;; determined by emacs' standard initialization
                           ;; procedure
                           (list ""))))
-                 #t))))))
+                 #t))))
+         #:include (cons* "^reporters/.*\\.el$" %default-include)))
       (home-page "https://github.com/rejeep/ert-runner.el")
       (synopsis "Opinionated Ert testing workflow")
       (description "@code{ert-runner} is a tool for Emacs projects tested