Rewritten KDoc-link resolve and completion to work more reasonably

idea/idea-completion/testData/kdoc/ExtensionsFQLink.kt

@@ -1,6 +1,10 @@
 package a
 
-class B {
+interface I
+
+class A : I
+
+class B : I {
     /**
      * [a.B.<caret>]
      */
@@ -10,11 +14,20 @@ class B {
 }
 
 fun B.ext() {
-
 }
 
 val B.extVal: String
     get() = ""
 
+fun A.wrongExt(){}
+
+val A.wrongExtVal: String
+    get() = ""
+
+fun I.extForSuper(){}
+
 // EXIST: ext
-// EXIST: extVal
+// EXIST: extVal
+// ABSENT: wrongExt
+// ABSENT: wrongExtVal
+// EXIST: extForSuper