docs: Fix TLS key length admonition

Author: sbernauer

docs/modules/secret-operator/pages/secretclass.adoc

@@ -51,12 +51,15 @@ include::example$secretclass-tls-key-length.yaml[]
 <2> `autoTls.ca.keyGeneration.rsa` specifies the RSA key pair algorithm (RSA currently is the only one supported)
 <3> `autoTls.ca.keyGeneration.rsa.length` specifies the amount of bits used for generating the RSA key pair. Currently, `2048`, `3072` and `4096` are supported. Defaults to `2048` bits.
 
-CAUTION: Using more than `2048` bits will significantly increase the computation time to create new key pairs.
+CAUTION
+====
+Using more than `2048` bits will significantly increase the computation time to create new key pairs.
 The SSL Labs https://github.com/ssllabs/research/wiki/SSL-and-TLS-Deployment-Best-Practices[SSL and TLS Deployment Best Practices] as of 2024-10-01 recommend
 
 >  For most websites, using RSA keys stronger than 2,048 bits and ECDSA keys stronger than 256 bits is a waste of CPU power and might impair user experience
 
 If options higher than `2048` are chosen, the CPU resources for the secret operator should be increased in order to avoid Pods being stuck in `Pending` waiting for the computation of their key pair.
+====
 
 ==== Certificate lifetime