chore: Fix some broken links or update to site-relative links

docs/reference/cloud-platform/dns.md

@@ -152,7 +152,7 @@ Google Chat.
 The [Lab Allocator](site:services/lab-allocator.md) product required a custom domain. A tutorial
 walkthrough of the process is available:
 
-* [Tutorial: Custom DNS for Cloud Platform Service](../../tutorials/gcp-custom-dns.md)
+* [Tutorial: Custom DNS for Cloud Platform Service](site:tutorials/gcp-custom-dns.md)
 
 ## Summary
 

docs/reference/cloud-platform/index.md

@@ -81,6 +81,6 @@ For more information on the configuration of these runners see [here](./gke-gitl
 ## Further information
 
 The rest of the pages in this section go into more detail on the specifics of our cloud platform
-environment. However, the [how-to](site:howtos/index.md) and [tutorial](../../tutorials)
+environment. However, the [how-to](site:howtos/index.md) and [tutorial](site:tutorials)
 sections are often a better place to start as they contain short, focussed, articles that are more
 relevant to day-to-day tasks.

docs/reference/deployment/web-applications.md

@@ -214,7 +214,7 @@ Using a Cloud Load balancer has the following advantages:
     to provide dynamic protection for the application.
 * Using [Cloud CDN](https://cloud.google.com/cdn) allows us to cache application
     static assets in Google's [Content delivery
-    network](//en.wikipedia.org/wiki/Content_delivery_network).
+    network](https://en.wikipedia.org/wiki/Content_delivery_network).
 * We can bring our own TLS certificates if we cannot make use of Google's
     auto-provisioning or there is a requirement to support EV/OV certificates.