Updates the hash used for the recent conversations view to be
"#recent" instead of "#recent_topics".
We will need to keep the logic for handling "#recent_topics"
permanently because users potentially have messages from
Welcome Bot with links to that hash.
Including "recent_topics" as a web_public_allowed_hash in
hash_util.js can be changed once self-hosted servers cannot
upgrade directly to Zulip 5.x from the current version.
Fixes#23132.
Replaces instances of "recent topics" in the web-app and documentation
to be "recent conversations".
Renames both `recent-topics.md` files in the help center to be
`recent-conversations.md` and updates/redirects links to new URL.
Does not update instances of "recent topics" in frontend code comments
and does not update the main overview changelog, for now.
Does not change case study text where "recent topics" was referenced
in a quote, but does change generic text references to be "recent
conversations".
We need to mark trailing bookends differently to identify them
in DOM easily. This fixes a bookend replication bug which can
happen sometimes when rendering.
We move the stream subscribed/unsubscribed bookend info from
js files to bookend handlebar.
Tweaked by tabbott to override the check-templates indentation logic.