Reverse zones: list other views' addresses, clearer wording

The zone page and jarl zone show list the addresses only other views'
records use (ptr_other_views_list), with the name each would get and the
view it comes from, and say plainly that they aren't missing here. The
page's button reads 'Add PTR records for them in view X'. zone show
lists the missing PTRs too.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -52,7 +52,9 @@ All notable changes to Jarl are documented here. The format follows
   (`fill_other_views`, `?other_views=1`, a checkbox in the New reverse
   zone dialog), so one view's host names don't leak into another. When
   there is nothing else to fill, Jarl says how many there are and how to
-  add them.
+  add them. The page and `jarl zone show` list those addresses with the
+  name each would get, and the view it comes from
+  (`ptr_other_views_list`); `jarl zone show` lists the missing ones too.
 
 - Records, zones and validation findings sort numeric labels by value, so
   `2.10.0.10.in-addr.arpa` comes before `101.10.0.10.in-addr.arpa` in the