add more verbose warnings regarding ssh_config in pillar.example

pillar.example

@@ -84,6 +84,11 @@ sshd_config:
     - 'hmac-ripemd160'
     - 'umac-128@openssh.com'
 
+# Warning! You should generally NOT NEED to set ssh_config. Setting ssh_config
+# pillar will overwrite the defaults of your distribution's SSH client. This
+# will also force the default configuration for all the SSH clients on the
+# machine. This can break SSH connections with servers using older versions of
+# openssh. Please make sure you understand the implication of different settings
 ssh_config:
   StrictHostKeyChecking: no
   ForwardAgent: no
@@ -107,9 +112,12 @@ ssh_config:
   PermitLocalCommand: 'no'
   VisualHostKey: 'no'
   # Check `man ssh_config` for supported KexAlgorithms, Ciphers and MACs first.
-  # You can specify KexAlgorithms, Ciphers and MACs as both key or a list.
+  # WARNING! Please make sure you understand the implications of the below
+  # settings. The examples provided below might break your connection to older /
+  # legacy openssh servers.
   # The configuration given in the example below is based on:
   # https://stribika.github.io/2015/01/04/secure-secure-shell.html
+  # You can specify KexAlgorithms, Ciphers and MACs as both key or a list.
   #KexAlgorithms: 'curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1'
   #Ciphers: 'chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr'
   #MACs: 'hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-ripemd160-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,hmac-ripemd160,umac-128@openssh.com'