Hotfix rewriteRun of #2713 which merged prematurely due to bug in #2725

Author: nedtwigg

lib/src/main/java/com/diffplug/spotless/markdown/FlexmarkConfig.java

@@ -15,11 +15,13 @@
  */
 package com.diffplug.spotless.markdown;
 
+import java.io.Serial;
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.List;
 
 public class FlexmarkConfig implements Serializable {
+	@Serial
 	private static final long serialVersionUID = 1L;
 
 	/**