help: Make loose lists title.

I missed converting `integrations-overview.md` since it was a file in
`api_docs` without realising that we had a symlink in help/ that pointed
to that file. I'm not sure how the other two files were missed but we
corrrect here nonetheless.

We have a few files where we have blank lines before tables and tips, we
need these blank lines for the current help center to render those
tables and tips properly. But those same blank lines make the list loose
when converted to MDX. We cannot make these changes before we have the
ability to modify MDX directly. We track this issue in #35533.

api_docs/integrations-overview.md

@@ -17,10 +17,8 @@ If you don't find an integration you need, you can:
 pull
 request](https://zulip.readthedocs.io/en/latest/contributing/reviewable-prs.html)
 to get your integration merged into the main Zulip repository.
-
 - [File an issue](https://github.com/zulip/zulip/issues/new/choose) to request
   an integration (if it's a nice-to-have).
-
 - [Contact Zulip Sales](mailto:sales@zulip.com) to inquire about a custom
   development contract.
 
@@ -106,13 +104,10 @@ Sales](mailto:sales@zulip.com).
 
 * If the third-party service supports outgoing webhooks, you likely want to
   build an [incoming webhook integration](/api/incoming-webhooks-overview).
-
 * If it doesn't, you may want to write a
   [script or plugin integration](/api/non-webhook-integrations).
-
 * The [`zulip-send` tool](/api/send-message) makes it easy to send Zulip
   messages from shell scripts.
-
 * Finally, you can
   [send messages using Zulip's API](/api/send-message), with bindings for
   Python, JavaScript and [other languages](/api/client-libraries).
@@ -122,7 +117,6 @@ Sales](mailto:sales@zulip.com).
 * To react to activity inside Zulip, look at Zulip's
   [Python framework for interactive bots](/api/running-bots) or
   [Zulip's real-time events API](/api/get-events).
-
 * If what you want isn't covered by the above, check out the full
   [REST API](/api/rest). The web, mobile, desktop, and terminal apps are
   built on top of this API, so it can do anything a human user can do. Most