doc: use single quotes in --tls-cipher-list

Currently, running the example code will produce the following error in
bash:
$ node --tls-cipher-list="ECDHE-RSA-AES128-GCM-SHA256:!RC4" server.js
bash: !RC4: event not found

This commit changes the two examples to use single quotes to avoid the
shell from trying to interpret '!' as the history command.

PR-URL: #33709
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

doc/api/tls.md

@@ -312,9 +312,9 @@ instance, the following makes `ECDHE-RSA-AES128-GCM-SHA256:!RC4` the default TLS
 cipher suite:
 
 ```bash
-node --tls-cipher-list="ECDHE-RSA-AES128-GCM-SHA256:!RC4" server.js
+node --tls-cipher-list='ECDHE-RSA-AES128-GCM-SHA256:!RC4' server.js
 
-export NODE_OPTIONS=--tls-cipher-list="ECDHE-RSA-AES128-GCM-SHA256:!RC4"
+export NODE_OPTIONS=--tls-cipher-list='ECDHE-RSA-AES128-GCM-SHA256:!RC4'
 node server.js
 ```