web: make Nth.Functional, Nth.Odd, Nth.Even private (#1633)

add corresponding public functions and values instead

Co-authored-by: Oleksandr Karpovich <oleksandr.karpovich@jetbrains.com>

web/core/src/jsMain/kotlin/org/jetbrains/compose/web/css/selectors/CSSSelectors.kt

@@ -8,7 +8,7 @@ internal const val webCssSelectorsDeprecationMessage = "Consider using a propert
 private val selectorScope = object : SelectorsScope {}
 
 sealed interface Nth {
-    data class Functional(val a: Int? = null, val b: Int? = null) : Nth {
+    private data class FunctionalImpl(val a: Int? = null, val b: Int? = null) : Nth {
         override fun toString(): String = when {
             a != null && b != null -> "${a}n+$b"
             a != null -> "${a}n"
@@ -16,12 +16,22 @@ sealed interface Nth {
             else -> ""
         }
     }
-    object Odd : Nth {
+    private object OddImpl : Nth {
         override fun toString(): String = "odd"
     }
-    object Even : Nth {
+    private object EvenImpl : Nth {
         override fun toString(): String = "even"
     }
+
+    companion object {
+        val Odd: Nth = OddImpl
+        val Even: Nth = EvenImpl
+
+        @Suppress("FunctionName") // we want it to look like old Functional class constructor
+        fun Functional(a: Int? = null, b: Int? = null): Nth {
+            return FunctionalImpl(a = a, b = b)
+        }
+    }
 }
 
 abstract class CSSSelector internal constructor() {

web/core/src/jsTest/kotlin/css/NthChildTests.kt

@@ -84,5 +84,4 @@ class NthChildTests {
             styleSheet.serializeRules()
         )
     }
-
-}
+}