Do not expect that KDoc reference contains importable fqName

#KT-31768 Fixed

Author: Alefas

idea/src/org/jetbrains/kotlin/idea/codeInsight/KotlinCopyPasteReferenceProcessor.kt

@@ -173,7 +173,7 @@ class KotlinCopyPasteReferenceProcessor : CopyPastePostProcessor<KotlinReference
 
                 if (!reference.canBeResolvedViaImport(descriptor, bindingContext)) continue
 
-                val fqName = descriptor.importableFqName!!
+                val fqName = descriptor.importableFqName ?: continue
                 val kind = KotlinReferenceData.Kind.fromDescriptor(descriptor) ?: continue
                 val isQualifiable = KotlinReferenceData.isQualifiable(ktElement, descriptor)
                 val relativeStart = ktElement.range.start - startOffset

idea/testData/copyPaste/imports/ClassWithDoc.expected.kt

@@ -0,0 +1,8 @@
+package goo
+
+import foo.Base
+
+/**
+ * @property param
+ */
+class Impl : Base(1)

idea/testData/copyPaste/imports/ClassWithDoc.expected.names

@@ -0,0 +1 @@
+foo.Base

idea/testData/copyPaste/imports/ClassWithDoc.kt

@@ -0,0 +1,8 @@
+package foo
+
+abstract class Base(val param: Int)
+
+<selection>/**
+ * @property param
+ */
+class Impl : Base(1)</selection>

idea/testData/copyPaste/imports/ClassWithDoc.to.kt

@@ -0,0 +1,3 @@
+package goo
+
+<caret>