Fix mbedtls_ssl_set_hostname documentation
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 0c1365c..82c0760 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -1781,10 +1781,11 @@
 
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
 /**
- * \brief          Set hostname for ServerName TLS extension
+ * \brief          Set the hostname to check against the received server
+ *                 certificate. It sets the ServerName TLS extension too,
+ *                 if the extension is enabled.
  *                 (client-side only)
  *
- *
  * \param ssl      SSL context
  * \param hostname the server hostname
  *