Navigate to receiver from this in extension function (KT-16991)

#KT-16991 Fixed
 #KT-13013 In Progress

idea/testData/navigation/gotoDeclaration/thisExtensionFunction.test

@@ -0,0 +1,18 @@
+// FILE: before.kt
+interface Foo
+
+fun foo(a: Any) {}
+
+fun Foo.bar() {
+    foo(this<caret>)
+}
+
+
+// FILE: after.kt
+interface Foo
+
+fun foo(a: Any) {}
+
+fun <caret>Foo.bar() {
+    foo(this)
+}