Initial support for KT-7090 Completion for callable references

#KT-7090 Fixed

idea/idea-completion/testData/basic/common/callableReference/NonEmptyQualifier.kt

@@ -0,0 +1,57 @@
+abstract class A {
+    abstract fun memberFunInA()
+    abstract val memberValInA: Int
+
+    inner class InnerInA
+    class NestedInA
+}
+
+fun A.extensionFun(){}
+
+val A.extensionVal: Int
+    get() = 1
+
+fun Any.anyExtensionFun(){}
+fun String.wrongExtensionFun(){}
+
+fun globalFun(p: Int) {}
+val globalVal = 1
+
+class C {
+    fun memberFun(){}
+
+    val memberVal = 1
+
+    fun A.memberExtensionFun(){}
+
+    fun foo() {
+        fun localFun(){}
+
+        val v = A::<caret>
+    }
+
+    companion object {
+        fun companionObjectFun(){}
+
+        fun A.companionExtension(){}
+    }
+}
+
+/* TODO // EXIST: class */
+/* TODO // EXIST: class.java */
+// EXIST: { itemText: "memberFunInA", attributes: "bold" }
+// EXIST: { itemText: "memberValInA", attributes: "bold" }
+// EXIST: { itemText: "InnerInA", attributes: "bold" }
+// EXIST: { itemText: "NestedInA", attributes: "" }
+// EXIST: { itemText: "extensionFun", attributes: "bold" }
+// EXIST: { itemText: "extensionVal", attributes: "bold" }
+// EXIST: { itemText: "anyExtensionFun", attributes: "" }
+// ABSENT: wrongExtensionFun
+// ABSENT: globalFun
+// ABSENT: globalVal
+// ABSENT: memberFun
+// ABSENT: memberVal
+// ABSENT: memberExtensionFun
+// ABSENT: localFun
+// ABSENT: companionObjectFun
+// ABSENT: companionExtension