Misc documentation fixes/improvements.
diff --git a/include/mbedtls/x509_crt.h b/include/mbedtls/x509_crt.h
index 961db98..afeefca 100644
--- a/include/mbedtls/x509_crt.h
+++ b/include/mbedtls/x509_crt.h
@@ -426,7 +426,7 @@
* \param flags result of the verification
* \param f_vrfy verification function
* \param p_vrfy verification parameter
- * \param rs_ctx restart context
+ * \param rs_ctx restart context (NULL to disable restart)
*
* \return See \c mbedtls_crt_verify_with_profile(), or
* \return #MBEDTLS_ERR_ECP_IN_PROGRESS if maximum number of