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/AutoCreatedIt.kt

@@ -4,7 +4,7 @@ fun text() {
     "direct:a" on {it -> it.body == "<hello/>"} to "mock:a"
     bar <!EXPECTED_PARAMETERS_NUMBER_MISMATCH!>{<!>1}
     bar <!EXPECTED_PARAMETERS_NUMBER_MISMATCH!>{<!><!UNRESOLVED_REFERENCE!>it<!> <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>+<!> 1}
-    bar {it, it1 -> it}
+    bar {it, <!UNUSED_PARAMETER!>it1<!> -> it}
 
     bar1 {1}
     bar1 {it + 1}
@@ -29,4 +29,4 @@ infix fun String.on(<!UNUSED_PARAMETER!>predicate<!> :  (s : URI) -> Boolean) :
 
 class URI(val body : Any) {
     infix fun to(<!UNUSED_PARAMETER!>dest<!> : String) {}
-}
+}