KT-15796 Import of class referenced only in KDoc not preserved after copy-paste

#KT-15796 fixed

compiler/frontend/src/org/jetbrains/kotlin/kdoc/psi/api/KDoc.kt

@@ -22,7 +22,7 @@ import org.jetbrains.kotlin.psi.KtDeclaration
 import org.jetbrains.kotlin.kdoc.parser.KDocKnownTag
 
 // Don't implement JetElement (or it will be treated as statement)
-interface KDoc : PsiComment {
+interface KDoc : PsiComment, KDocElement {
     fun getOwner(): KtDeclaration?
     fun getDefaultSection(): KDocSection
     fun findSectionByName(name: String): KDocSection?

compiler/frontend/src/org/jetbrains/kotlin/kdoc/psi/impl/KDocElementImpl.java

@@ -21,8 +21,9 @@ import com.intellij.lang.ASTNode;
 import com.intellij.lang.Language;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.kotlin.idea.KotlinLanguage;
+import org.jetbrains.kotlin.kdoc.psi.api.KDocElement;
 
-public abstract class KDocElementImpl extends ASTWrapperPsiElement {
+public abstract class KDocElementImpl extends ASTWrapperPsiElement implements KDocElement {
     @NotNull
     @Override
     public Language getLanguage() {