doc: optimize the doc about Unix abstract socket

Author: theanarkh

doc/api/net.md

@@ -39,9 +39,10 @@ socket outside of these abstractions, the user will need to remove it. The same
 applies when a Node.js API creates a Unix domain socket but the program then
 crashes. In short, a Unix domain socket will be visible in the file system and
 will persist until unlinked. On Linux, You can use Unix abstract socket by adding
-`\0` to the beginning of the path, such as `\0abstract`. The path to the Unix
-abstract socket is not visible in the file system and it will disappear automatically
-when all open references to the socket are closed.
+`\0` to the beginning of the path, such as `\0abstract` (Only available in
+Node.js >= v20.8.0). The path to the Unix abstract socket is not visible in the
+file system and it will disappear automatically when all open references to the
+socket are closed.
 
 On Windows, the local domain is implemented using a named pipe. The path _must_
 refer to an entry in `\\?\pipe\` or `\\.\pipe\`. Any characters are permitted,