Update MentOs code to the latest development version.

programs/clear.c

@@ -0,0 +1,13 @@
+///                MentOS, The Mentoring Operating system project
+/// @file clear.c
+/// @brief `clear` program.
+/// @copyright (c) 2014-2021 This file is distributed under the MIT License.
+/// See LICENSE.md for details.
+
+#include <stdio.h>
+
+int main(int argc, char **argv)
+{
+    puts("\033[J");
+    return 0;
+}