Use a function to generate do-not-edit comment

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/10316)
diff --git a/doc/man1/openssl-genrsa.pod.in b/doc/man1/openssl-genrsa.pod.in
index 6239cd8..16b887b 100644
--- a/doc/man1/openssl-genrsa.pod.in
+++ b/doc/man1/openssl-genrsa.pod.in
@@ -1,9 +1,5 @@
 =pod
-
-=begin comment
-{- join("\n", @autowarntext) -}
-
-=end comment
+{- OpenSSL::safe::output_do_not_edit_headers(); -}
 
 =head1 NAME