docs: Rename customize.html to settings.html.

This is a better description of what this is for.

docs/production/index.rst

@@ -9,7 +9,7 @@ Zulip in Production
    requirements
    Installing a production server <install>
    troubleshooting
-   customize
+   settings
    mobile-push-notifications
    maintain-secure-upgrade
    security-model

docs/production/install.md

@@ -78,7 +78,7 @@ dependencies from the PyPI and NPM repositories.
   If you'd prefer to acquire an SSL certificate yourself in any other
   way, it's easy to [provide it to Zulip][doc-ssl-manual].
 
-[doc-settings]: ../production/customize.html
+[doc-settings]: ../production/settings.html
 [doc-certbot]: ../production/ssl-certificates.html#certbot-recommended
 [doc-ssl-manual]: ../production/ssl-certificates.html#manual-install
 
@@ -178,7 +178,7 @@ to get important announcements for Zulip server administrators about
 new releases, security issues, etc.
 * [Follow Zulip on Twitter](https://twitter.com/zulip) to get Zulip news.
 * [Learn how to setup your new Zulip organization][realm-admin-docs].
-* [Learn how further configure your Zulip server](customize.html).
+* [Learn how configure your Zulip server settings](settings.html).
 * [Learn about maintaining a production Zulip server](../production/maintain-secure-upgrade.html).
 
 ## Troubleshooting

docs/production/overview.md

@@ -36,7 +36,7 @@ You now have a running Zulip install!
 * Read [our advice on helping your community][realm-admin-docs] make
   the most of Zulip.
 
-* [Customize Zulip](customize.html) to your needs.
+* [Customize Zulip](settings.html) by configuring the server-level settings.
 
 * Read about Zulip's support for backups, monitoring, and
   other [important production considerations](../production/maintain-secure-upgrade.html).

docs/production/troubleshooting.md

@@ -129,5 +129,3 @@ problems and how to resolve them:
   not have the correct HTTP Host header, Django rejects it and logs the
   attempt. For more on this issue, see the [Django release notes on Host header
   poisoning](https://www.djangoproject.com/weblog/2013/feb/19/security/#s-issue-host-header-poisoning)
-
-Next: [Making your Zulip instance awesome.](customize.html)