funced: don't source or save unmodified files

If funced is just used to inspect a function, there's no need to write
it to storage or to reload it.

share/functions/funced.fish

@@ -104,6 +104,8 @@ function funced --description 'Edit function definition'
                 set -l new_checksum (__funced_md5 "$tmpname")
                 if test "$new_checksum" = "$checksum"
                     echo (_ "Editor exited but the function was not modified")
+                    # Don't source or save an unmodified file.
+                    break
                 end
             end