[java-psi] Add implicit classes to preceding comment set

Fixes IDEA-355602 Implicit class parsing: Javadoc is not attached to the method

GitOrigin-RevId: bd18f57e8106618aa741203e6cb3f4cd8cffe13d

java/java-tests/testData/psi/parser-full/declarationParsing/class/ImplicitClassJavaDoc.java

@@ -0,0 +1,6 @@
+/**
+ * Main method
+ */
+public static void main() {
+  System.out.println("Hello");
+}