doc: fix initial default value of autoSelectFamily

Specify the initial default value of `autoSelectFamily`
in description of `net.setDefaultAutoSelectFamily()`
as specified in description of `net.getDefaultAutoSelectFamily()`.

PR-URL: #55245
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Paolo Insogna <paolo@cowtech.it>
Reviewed-By: Jake Yuesong Li <jake.yuesong@gmail.com>

Author: freego555

doc/api/net.md

@@ -1798,7 +1798,9 @@ added: v19.4.0
 
 Sets the default value of the `autoSelectFamily` option of [`socket.connect(options)`][].
 
-* `value` {boolean} The new default value. The initial default value is `false`.
+* `value` {boolean} The new default value.
+  The initial default value is `true`, unless the command line option
+  `--no-network-family-autoselection` is provided.
 
 ## `net.getDefaultAutoSelectFamilyAttemptTimeout()`