(describe-function): Mention the file it was loaded from.

lisp/help.el

@@ -388,27 +388,33 @@ C-w print information on absence of warranty for GNU Emacs."
 	   (beg (if (commandp def) "an interactive " "a ")))
       (princ (cond ((or (stringp def)
 			(vectorp def))
-		    "a keyboard macro.")
+		    "a keyboard macro")
 		   ((subrp def)
-		    (concat beg "built-in function."))
+		    (concat beg "built-in function"))
 		   ((byte-code-function-p def)
-		    (concat beg "compiled Lisp function."))
+		    (concat beg "compiled Lisp function"))
 		   ((symbolp def)
-		    (format "alias for `%s'." def))
+		    (format "alias for `%s'" def))
 		   ((eq (car-safe def) 'lambda)
-		    (concat beg "Lisp function."))
+		    (concat beg "Lisp function"))
 		   ((eq (car-safe def) 'macro)
-		    "a Lisp macro.")
+		    "a Lisp macro")
 		   ((eq (car-safe def) 'mocklisp)
-		    "a mocklisp function.")
+		    "a mocklisp function")
 		   ((eq (car-safe def) 'autoload)
-		    (format "%s autoloaded Lisp %s."
+		    (format "%s autoloaded Lisp %s"
 			    (if (commandp def) "an interactive" "an")
 			    (if (nth 4 def) "macro" "function")
 ;;; Including the file name made this line too long.
 ;;;			    (nth 1 def)
 			    ))
 		   (t "")))
+      (if (get function 'autoload)
+	  (progn
+	    (princ " in the `")
+	    (princ (car (get function 'autoload)))
+	    (princ "' package")))
+      (princ ".")
       (terpri)
       (let ((arglist (cond ((byte-code-function-p def)
 			    (car (append def nil)))