[Support] Update Support KB links

[pedrosousa]

Summary

Old-style Support KB links prevent us from doing automatic broken link checking for these pages.
Updating these links to Dev Docs (relative) links.

Documentation checklist

• The documentation style guide has been adhered to.

[github-actions]

This pull request requires reviews from CODEOWNERS as it changes files that match the following patterns:

Pattern	Owners
/src/content/docs/support/	@zeinjaber, @ngayerie, @cloudflare/pcx-technical-writing, @cloudflare/customer-support
/src/content/docs/workers/	@cloudflare/workers-docs, @GregBrimble, @irvinebroque, @mikenomitch, @korinne, @WalshyDev, @cloudflare/deploy-config, @cloudflare/pcx-technical-writing, @kodster28, @cloudflare/wrangler, @cloudflare/workers-runtime-1

[github-actions]

Preview URL: https://cb31f360.preview.developers.cloudflare.com
Preview Branch URL: https://pedro-2025-09-25-support-update-old-links.preview.developers.cloudflare.com

Files with changes (up to 15)

Original Link	Updated Link
https://developers.cloudflare.com/support/third-party-software/content-management-system-cms/wordpresscom-and-cloudflare/	https://pedro-2025-09-25-support-update-old-links.preview.developers.cloudflare.com/support/third-party-software/content-management-system-cms/wordpresscom-and-cloudflare/
https://developers.cloudflare.com/workers/testing/miniflare/core/fetch/	https://pedro-2025-09-25-support-update-old-links.preview.developers.cloudflare.com/workers/testing/miniflare/core/fetch/
https://developers.cloudflare.com/support/customer-incident-management-policy/	https://pedro-2025-09-25-support-update-old-links.preview.developers.cloudflare.com/support/customer-incident-management-policy/
https://developers.cloudflare.com/support/third-party-software/content-management-system-cms/cloudflare-wordpress-plugin-automatic-cache-management/	https://pedro-2025-09-25-support-update-old-links.preview.developers.cloudflare.com/support/third-party-software/content-management-system-cms/cloudflare-wordpress-plugin-automatic-cache-management/
https://developers.cloudflare.com/support/third-party-software/content-management-system-cms/how-do-i-enable-http2-server-push-in-wordpress/	https://pedro-2025-09-25-support-update-old-links.preview.developers.cloudflare.com/support/third-party-software/content-management-system-cms/how-do-i-enable-http2-server-push-in-wordpress/
https://developers.cloudflare.com/support/third-party-software/others/configure-cloudflare-and-heroku-over-https/	https://pedro-2025-09-25-support-update-old-links.preview.developers.cloudflare.com/support/third-party-software/others/configure-cloudflare-and-heroku-over-https/
https://developers.cloudflare.com/support/troubleshooting/restoring-visitor-ips/restoring-original-visitor-ips/	https://pedro-2025-09-25-support-update-old-links.preview.developers.cloudflare.com/support/troubleshooting/restoring-visitor-ips/restoring-original-visitor-ips/