check_http first lines

docs/20_Checks/_index.md

@@ -25,6 +25,7 @@ There is one include script used by all checks:
 * [check_fs_writable](check_fs_writable.md)
 * [check_haproxy_health](check_haproxy_health.md)
 * [check_haproxy_status](check_haproxy_status.md)
+* [check_http](check_http.md)
 * [check_memory](check_memory.md)
 * [check_mysqlserver](check_mysqlserver.md)
 * [check_netio](check_netio.md)