feat: change font and release greate tty output

kernel/src/mem/pmm.rs

@@ -71,7 +71,7 @@ impl BitmapPMM {
         *PMM.lock() = Some(pmm);
     }
 
-    // ── Core operations ───────────────────────────────────────────────────────
+    //Core operations
 
     /// Mark a frame as free.  Idempotent (double-free is a no-op, not UB).
     pub fn free_frame(&mut self, phys_addr: PhysAddr) {
@@ -175,7 +175,7 @@ impl BitmapPMM {
     }
 }
 
-// ── Module-level convenience functions ───────────────────────────────────────
+//Module-level convenience functions
 
 pub fn alloc_frame() -> Option<PhysAddr> {
     PMM.lock().as_mut()?.alloc_frame()