mu/mu4e: tweak :list vs :mailing list

lib/message/mu-fields.hh

@@ -320,7 +320,7 @@ static constexpr std::array<Field, Field::id_size()>
 	    {
 		Field::Id::MailingList,
 		Field::Type::String,
-		"mailing-list", "list",
+		"list", {},
 		"Mailing list (List-Id:)",
 		"list:mu-discuss.example.com",
 		'v',

mu4e/mu4e-headers.el

@@ -561,7 +561,7 @@ found."
         ;; so limit subject length to 600
         (truncate-string-to-width val 600)))
       (:thread-subject (mu4e~headers-thread-subject msg))
-      ((:maildir :path :message-id) val)
+      ((:maildir :path :message-id :list) val)
       ((:to :from :cc :bcc) (mu4e~headers-contact-str val))
       ;; if we (ie. `user-mail-address' is the 'From', show
       ;; 'To', otherwise show From
@@ -1387,7 +1387,7 @@ matching messages with that mark."
                                     ("to"      . :to)
                                     ("cc"      . :cc)
                                     ("bcc"     . :bcc)
-                                    ("list"    . :mailing-list))))
+                                    ("list"    . :list))))
         (pattern (read-string
                   (mu4e-format "Regexp:")
                   nil 'mu4e~headers-regexp-hist)))

mu4e/mu4e-view.el

@@ -778,8 +778,11 @@ determine which browser function to use."
 	(dolist (field mu4e-view-fields)
 	  (let ((fieldval (mu4e-message-field msg field)))
 	    (pcase field
-	      ((or ':path ':maildir ':user-agent ':mailing-list ':message-id)
+	      ((or ':path ':maildir :list ':user-agent ':message-id)
 	       (mu4e~view-gnus-insert-header field fieldval))
+	      (':mailing-list
+	       (let ((list (plist-get msg :list)))
+		 (if list (mu4e-get-mailing-list-shortname list) "")))
 	      ((or ':flags ':tags)
 	       (let ((flags (mapconcat (lambda (flag)
 					 (if (symbolp flag)