Are string templates supported yet?

Hi all, 

I'm trying to play around with String Templates under JDK 21 using IntelliJ IDEA 2023.2.1 (Ultimate Edition)

I tried setting this on project and module level and added it to maven pom file.

String name = "moo";
String message = STR."Greetings \{name}!";  //Java
System.out.println(message);
 

java: string templates are a preview feature and are disabled by default.
 (use --enable-preview to enable string templates)

I notice we don't have 21 yet in the language level selection.  I guess it's still not ready?