fix: Correction of the CheckStyle issue the project acyclic-visitor (#1969)

Author: HattoriHenzo

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Modem.java

@@ -28,5 +28,5 @@
  * converted to an interface
  */
 public interface Modem {
-   void accept(ModemVisitor modemVisitor);
+  void accept(ModemVisitor modemVisitor);
 }