refactoring: squareRootPlusOne function test, rename

src/test/test_funktionen.c

@@ -198,7 +198,7 @@ void test_naturalLogarithmPlusOne_for_10_0(void) {
 
 }
 
-void test_squareRootPlusOne(void) {
+void test_squareRootPlusOne_for_9_0(void) {
     float result = squareRootPlusOne(9.0);
     TEST_ASSERT_EQUAL_FLOAT(4.0, result);
     // Add more test cases for different inputs and expected outputs