clarify the behavior
diff --git a/lib/openssl.c b/lib/openssl.c
index fe3d0cc..05f82a2 100644
--- a/lib/openssl.c
+++ b/lib/openssl.c
@@ -1008,7 +1008,7 @@
ptls_openssl_sign_certificate_t *self = (ptls_openssl_sign_certificate_t *)_self;
const struct st_ptls_openssl_signature_scheme_t *scheme;
- /* select the algorithm */
+ /* select the algorithm (driven by server-side preference of `self->schemes`) */
for (scheme = self->schemes; scheme->scheme_id != UINT16_MAX; ++scheme) {
size_t i;
for (i = 0; i != num_algorithms; ++i)