Initial support for KT-7090 Completion for callable references

#KT-7090 Fixed

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

@@ -0,0 +1,7 @@
+import java.io.File
+
+val v = File::<caret>
+
+// EXIST_JAVA_ONLY: { itemText: "freeSpace", tailText: " (from getFreeSpace())", attributes: "bold" }
+// EXIST_JAVA_ONLY: { itemText: "isFile", tailText: " (from isFile())", attributes: "bold" }
+// ABSENT: { itemText: "isFile", tailText: "()" }