doc: do not use "Returns:" for crypto.constants

This is not a function and should not use the term "return" to describe
its type or value.

PR-URL: nodejs#44481
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Harshitha K P <harshitha014@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

doc/api/crypto.md

@@ -2871,9 +2871,11 @@ Does not perform any other validation checks on the certificate.
 added: v6.3.0
 -->
 
-* Returns: {Object} An object containing commonly used constants for crypto and
-  security related operations. The specific constants currently defined are
-  described in [Crypto constants][].
+* {Object}
+
+An object containing commonly used constants for crypto and security related
+operations. The specific constants currently defined are described in
+[Crypto constants][].
 
 ### `crypto.DEFAULT_ENCODING`