Update printf_argument.c

Replaced \n with \c Exercise 1-2 was to find out what happens when string contains \c, not \n

Author: MuhammadSalah-MS

chapter_1/exercise_1_02/printf_argument.c

@@ -2,6 +2,6 @@
 
 int main(void)
 {
- printf("hello: \n");
+ printf("hello, world\c");
  return 0;
 }