added Java Doc in TextTest.java

test/TextTest.java

@@ -31,6 +31,9 @@ public class TextTest {
         Assertions.assertEquals(4, txt.getText().size());
     }
 
+    /**
+     * Test Method for replace Method
+     */
     @Test
     void replace() {
         Assertions.assertEquals(true, txt.add("Das ist der erste Beispiel Text."));