kernel: Avoid printing control characters that we don't have a special meaning for

kernel/src/video/TextConsole.cpp

@@ -2,6 +2,7 @@
 #include "boot/bootboot.h"
 #include "video/Framebuffer.h"
 #include <luna/CString.h>
+#include <luna/CType.h>
 #include <luna/Format.h>
 #include <luna/Result.h>
 #include <luna/ScopeGuard.h>
@@ -109,6 +110,7 @@ namespace TextConsole
             }
             break;
         default: {
+            if (_iscntrl(c)) return;
             putwchar_at(c, g_x_position, g_y_position);
             next_char();
             if (at_end_of_screen())