Create from Usage: Suggest synthetic function classes as extension receivers

idea/testData/quickfix/createFromUsage/createFunction/call/functionalTypeInReceiver.kt

@@ -0,0 +1,5 @@
+// "Create extension function 'bar'" "true"
+
+fun foo(block: (Int) -> String) {
+    block.b<caret>ar()
+}

idea/testData/quickfix/createFromUsage/createFunction/call/functionalTypeInReceiver.kt.after

@@ -0,0 +1,9 @@
+// "Create extension function 'bar'" "true"
+
+fun foo(block: (Int) -> String) {
+    block.bar()
+}
+
+fun <P1, R> ((P1) -> R).bar() {
+    throw UnsupportedOperationException("not implemented") //To change body of created functions use File | Settings | File Templates.
+}