docs: fix formating

subjects/java/checkpoints/good-by-mars/README.md

@@ -1,14 +1,14 @@
-## HelloWorld
+## GoodbyMars
 
 ### Instructions
 
-In a file named `HelloWorld.java` write a function `helloWorld` that returns the string 'Hello World !'.
+In a file named `GoodbyMars.java` write a function `goodbyMars` that returns the string 'Good by Mars !'.
 
 ### Expected Functions
 
 ```java
-public class HelloWorld {
-    public static String helloWorld() {
+public class GoodbyMars {
+    public static String goodbyMars() {
         // your code here
     }
 }
@@ -21,7 +21,7 @@ Here is a possible ExerciseRunner.java to test your function :
 ```java
 public class ExerciseRunner {
     public static void main(String[] args) {
-        System.out.println(HelloWorld.helloWorld());
+        System.out.println(GoodbyMars.goodbyMars());
     }
 }
 ```
@@ -31,6 +31,6 @@ and its output :
 ```shell
 $ javac *.java -d build
 $ java -cp build ExerciseRunner
-Hello World !
+Good by Mars !
 $
 ```

subjects/java/checkpoints/universal-greeting/README.md

@@ -4,9 +4,11 @@
 
 In a file named `UniversalGreeting.java` write a function `greeting` that takes a String language as a parameter and returns a greeting message based on the language as follows:
 
-FR : Bonjour comment allez-vous
-EN : Hello, How are you
-ES : Hola, cómo estás
+`FR` : `Bonjour comment allez-vous?`
+`EN`: `Hello, How are you?`
+`ES` : `Hola, cómo estás?`
+
+and return an empty string in any other case.
 
 ### Expected Functions