Minor fix

notes/计算机操作系统.md

@@ -613,7 +613,7 @@ void philosopher(int i) {
         think();
         take_two(i);
         eat();
-        put_tow(i);
+        put_two(i);
     }
 }
 
@@ -625,7 +625,7 @@ void take_two(int i) {
     down(&s[i]);
 }
 
-void put_tow(i) {
+void put_two(i) {
     down(&mutex);
     state[i] = THINKING;
     test(LEFT);