Revert "Don't tag Gnus bugs with "gnus""

This reverts commit b6fa580723.

The debbugs syntax requires a package name

lisp/gnus/gnus-msg.el

@@ -1535,7 +1535,11 @@ If YANK is non-nil, include the original article."
       (message-pop-to-buffer "*Gnus Bug*"))
     (let ((message-this-is-mail t))
       (message-setup `((To . ,gnus-maintainer)
-                       (Subject . ""))))
+                       (Subject . "")
+                       (X-Debbugs-Package
+                        . ,(format "%s" gnus-bug-package))
+                       (X-Debbugs-Version
+                        . ,(format "%s" (gnus-continuum-version))))))
     (when gnus-bug-create-help-buffer
       (push `(gnus-bug-kill-buffer) message-send-actions))
     (goto-char (point-min))

lisp/gnus/gnus.el

@@ -2654,6 +2654,10 @@ such as a mark that says whether an article is stored in the cache
   "submit@debbugs.gnu.org (The Gnus Bugfixing Girls + Boys)"
   "The mail address of the Gnus maintainers.")
 
+(defconst gnus-bug-package
+  "gnus"
+  "The package to use in the bug submission.")
+
 (defvar gnus-info-nodes
   '((gnus-group-mode "(gnus)Group Buffer")
     (gnus-summary-mode "(gnus)Summary Buffer")