Update docs/configuring-dns.md: add "Note" to the line on using Cloudflare DNS

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

docs/configuring-dns.md

@@ -36,7 +36,7 @@ The `element.example.com` subdomain is necessary, because this playbook installs
 
 Be mindful as to how long it will take for the DNS records to propagate.
 
-If you are using Cloudflare DNS, make sure to disable the proxy and set all records to "DNS only". Otherwise, fetching certificates will fail.
+**Note**: if you are using Cloudflare DNS, make sure to disable the proxy and set all records to "DNS only". Otherwise, fetching certificates will fail.
 
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