rename tbs_certificate to tbs_certificate_bytes, add a comment
diff --git a/docs/x509/reference.rst b/docs/x509/reference.rst
index bac48ab..10ba9ec 100644
--- a/docs/x509/reference.rst
+++ b/docs/x509/reference.rst
@@ -390,7 +390,7 @@
 
         The bytes of the certificate's signature.
 
-    .. attribute:: tbs_certificate
+    .. attribute:: tbs_certificate_bytes
 
         .. versionadded:: 1.2