refactoring: test_factorial_of_5 rename

src/test/test_funktionen.c

@@ -48,7 +48,7 @@ void test_naturalLogarithm_for_100(void) {
 }
 
 
-void test_factorial(void) {
+void test_factorial_of_5(void) {
     int result = factorial(5);
     TEST_ASSERT_EQUAL_INT(120, result);
 }