Fix referenses in section 3 manuals

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1900)
diff --git a/doc/man3/DH_generate_key.pod b/doc/man3/DH_generate_key.pod
index de0847a..297e7fb 100644
--- a/doc/man3/DH_generate_key.pod
+++ b/doc/man3/DH_generate_key.pod
@@ -40,7 +40,7 @@
 
 =head1 SEE ALSO
 
-L<dh(3)>, L<ERR_get_error(3)>, L<rand(3)>, L<DH_size(3)>
+L<DH_new(3)>, L<ERR_get_error(3)>, L<RAND_bytes(3)>, L<DH_size(3)>
 
 =head1 COPYRIGHT