Fix magic comments

src/main/java/interpreter/Evaluator.java

@@ -20,7 +20,7 @@ with
 - an integer `z`.
 */
 
-/*- Header */
+/*!- Header */
 package interpreter;
 
 import expression.*;

src/main/java/interpreter/InterpreterException.java

@@ -5,7 +5,7 @@ InterpreterException
 ====================
 */
 
-/*- Header */
+/*!- Header */
 package interpreter;
 
 /*! The `InterpreterException` is raised if anything goes wrong during the evaluation of an `Expression` or

src/main/java/interpreter/Visitor.java

@@ -12,7 +12,7 @@ and in Java this is typically implemented using the
 [Visitor Pattern](https://en.wikipedia.org/wiki/Visitor_pattern).
 */
 
-/*- Header */
+/*!- Header */
 package interpreter;
 
 

src/main/java/parser/SyntaxException.java

@@ -5,7 +5,7 @@ SyntaxException
 ===============
 */
 
-/*- Header */
+/*!- Header */
 package parser;
 
 /*! A `SyntaxException` is raised by the function in the `Parser` if an expected was not found at the current