correct the docs for CRLReason (#3930)

diff --git a/docs/x509/reference.rst b/docs/x509/reference.rst
index f07272a..2e86cb1 100644
--- a/docs/x509/reference.rst
+++ b/docs/x509/reference.rst
@@ -2319,8 +2319,7 @@
     valid inside :class:`~cryptography.x509.RevokedCertificate` objects. It
     identifies a reason for the certificate revocation.
 
-    :param reason: A value from the
-        :class:`~cryptography.x509.oid.CRLEntryExtensionOID` enum.
+    :param reason: An element from :class:`~cryptography.x509.ReasonFlags`.
 
     .. attribute:: oid