refactoring: added function comments

src/fakultaet/fakultaet.c

@@ -1,9 +1,11 @@
 #include <stdio.h>
 
 int fakultaet(int n) {
+	// Checking if the input is either zero or one
 	if (n == 0 || n == 1)
 		return 1;
 
+	// The result multiplies with i and i increases every turn until the loop ends
 	int result = 1;
 	for (int i = 2; i <= n; i++) {
 		result *= i;