small fix of the vga buffer fn

Author: git-user-cpp

os/kernel/core/vga_output.rs

@@ -1,7 +1,7 @@
-pub fn vga_output_message(HELLO: &[u8]) {
+pub fn vga_output_message(message: &[u8]) {
     let vga_buffer = 0xb8000 as *mut u8;
 
-    for(i, &byte) in HELLO.iter().enumerate(){
+    for(i, &byte) in message.iter().enumerate(){
         unsafe {
             *vga_buffer.offset(i as isize * 2) = byte;
             *vga_buffer.offset(i as isize * 2 + 1) = 0xb;