Backport commit 2a8d08360 from Emacs

The w3 package was removed from GNU ELPA in 2020 as it doesn't run on
a recent Emacs, and development had stopped over a decade before that.
If anyone wants to revive the w3 package, they should look this all
over, but it doesn't make sense for us to maintain this support code.
Ref: https://debbugs.gnu.org/25395

* lisp/ol.el (org-store-link): Remove w3 support code and related
documentation and comments.  (Bug#56435)
* doc/org-manual.org (Handling Links): Don't mention W3.

Drop support for the dead third-party w3 package
2a8d083607e7e0fe9358f1f6526dbd8aa928af61
Stefan Kangas
Sat Jul 9 17:27:49 2022 +0200

doc/org-manual.org

@@ -3352,7 +3352,7 @@ current buffer:
   ~org-link-email-description-format~.  By default, it refers to the
   addressee and the subject.
 
-- /Web browsers: W3, W3M and EWW/ ::
+- /Web browsers: W3M and EWW/ ::
 
   Here the link is the current URL, with the page title as the
   description.

lisp/ol.el

@@ -1580,14 +1580,6 @@ non-nil."
 			      nil nil nil))))
 	  (org-link-store-props :type "calendar" :date cd)))
 
-       ((eq major-mode 'w3-mode)
-	(setq cpltxt (if (and (buffer-name)
-			      (not (string-match "Untitled" (buffer-name))))
-			 (buffer-name)
-		       (url-view-url t))
-	      link (url-view-url t))
-	(org-link-store-props :type "w3" :url (url-view-url t)))
-
        ((eq major-mode 'image-mode)
 	(setq cpltxt (concat "file:"
 			     (abbreviate-file-name buffer-file-name))