Report warning on unused entities that can be renamed to _

Currently it's all about lambda parameters/destructuring entries

 #KT-14347 In Progress

compiler/testData/diagnostics/tests/syntheticExtensions/samAdapters/GenericClass.kt

@@ -1,6 +1,6 @@
 // FILE: KotlinFile.kt
 fun foo(javaClass: JavaClass<String>): String {
-    return javaClass.doSomething("", 1) { s: String -> "" }
+    return javaClass.doSomething("", 1) { <!UNUSED_PARAMETER!>s<!>: String -> "" }
 }
 
 // FILE: JavaClass.java
@@ -10,4 +10,4 @@ public class JavaClass<T> {
 
 interface I<T> {
     T doIt(T t);
-}
+}