gnus-article-view-part: Doc fix by Lars Magne Ingebrigtsen <larsi@gnus.org>.

lisp/gnus/ChangeLog

 2010-08-30  Lars Magne Ingebrigtsen  <larsi@gnus.org>
 
+	* gnus-art.el (gnus-article-view-part): Doc fix.
+
 	* gnus-html.el (gnus-html-put-image): Use gnus-create-image to be
 	XEmacs-compatible.
 	(gnus-html-put-image): Don't do images on non-graphic displays.

lisp/gnus/gnus-art.el

@@ -5549,7 +5549,9 @@ N is the numerical prefix."
     1))
 
 (defun gnus-article-view-part (&optional n)
-  "View MIME part N, which is the numerical prefix."
+  "View MIME part N, which is the numerical prefix.
+If the part is already shown, hide the part.  If N is nil, view
+all parts."
   (interactive "P")
   (with-current-buffer gnus-article-buffer
     (or (numberp n) (setq n (gnus-article-mime-match-handle-first