[FIR] Improve diagnostic reporting & don't use error symbol for candidate if possible

Also introduce few new diagnostics:
- NONE_APPLICABLE more many inapplicable candidates
- HIDDEN for visible candidates

compiler/testData/diagnostics/tests/imports/invisibleFakeReferenceInImport.fir.kt

@@ -3,7 +3,7 @@
 import B.foo
 
 fun test() {
-    <!INAPPLICABLE_CANDIDATE!>foo<!>
+    <!HIDDEN!>foo<!>
 }
 
 // FILE: B.kt
@@ -13,4 +13,4 @@ object B : C<String>()
 
 open class C<T> {
     private var foo: String = "abc"
-}
+}