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/inference/reportingImprovements/ErrorTypeAsGenericParameter.kt

@@ -3,7 +3,7 @@ package a
 fun <T, R, S> foo(block: (T)-> R, <!UNUSED_PARAMETER!>second<!>: (T)-> S) = block
 
 fun main(args: Array<String>) {
-    val fff = { x: Int -> <!UNRESOLVED_REFERENCE!>aaa<!> }
+    val fff = { <!UNUSED_PARAMETER!>x<!>: Int -> <!UNRESOLVED_REFERENCE!>aaa<!> }
     foo(<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>fff<!>, { x -> x + 1 })
 }
 

compiler/testData/diagnostics/tests/inference/reportingImprovements/NoAmbiguityForDifferentFunctionTypes.kt

@@ -9,7 +9,7 @@ fun <T: Closeable, R> T.foo(block: (T, T)-> R) = block
 
 fun main(args: Array<String>) {
     C().foo { // no ambiguity here
-        www ->
+        <!UNUSED_PARAMETER!>www<!> ->
         <!UNRESOLVED_REFERENCE!>xs<!>
     }
 }

compiler/testData/diagnostics/tests/inference/reportingImprovements/cannotInferParameterTypeWithInference.kt

@@ -4,7 +4,7 @@ fun <T, R> foo(block: (T)-> R) = block
 
 fun test1() {
     <!TYPE_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>foo<!> {
-        <!CANNOT_INFER_PARAMETER_TYPE!>x<!> ->  // here we have 'cannot infer parameter type' error
+        <!CANNOT_INFER_PARAMETER_TYPE, UNUSED_PARAMETER!>x<!> ->  // here we have 'cannot infer parameter type' error
         43
     }
 }
@@ -12,5 +12,5 @@ fun test1() {
 fun bar(<!UNUSED_PARAMETER!>f<!>: (<!UNRESOLVED_REFERENCE!>A<!>)->Unit) {}
 
 fun test2() {
-    bar { a -> } // here we don't have 'cannot infer parameter type' error
-}
+    bar { <!UNUSED_PARAMETER!>a<!> -> } // here we don't have 'cannot infer parameter type' error
+}