Make "Specify explicit lambda signature" available on whole lambda

So #KT-22492 Fixed

idea/testData/quickfix/replaceWithSafeCallForScopeFunction/letWithWrongImplicitThis.kt

@@ -4,6 +4,7 @@
 // ACTION: Introduce local variable
 // ACTION: Move lambda argument into parentheses
 // ACTION: Replace with safe (this?.) call
+// ACTION: Specify explicit lambda signature
 // ERROR: Only safe (?.) or non-null asserted (!!.) calls are allowed on a nullable receiver of type String?
 
 fun String?.foo(a: String?) {