chore: Using conventional name and renaming isPolimorphic

Author: LichtHund

formats/hocon/src/main/kotlin/kotlinx/serialization/hocon/Hocon.kt

@@ -145,7 +145,7 @@ public sealed class Hocon(
 
     }
 
-    private inner class ConfigReader(val conf: Config, private val isPolymorph: Boolean = false) : ConfigConverter<String>() {
+    private inner class ConfigReader(val conf: Config, private val isPolymorphic: Boolean = false) : ConfigConverter<String>() {
         private var ind = -1
 
         override fun decodeElementIndex(descriptor: SerialDescriptor): Int {
@@ -162,10 +162,8 @@ public sealed class Hocon(
             if (parentName.isEmpty()) childName else "$parentName.$childName"
 
         override fun SerialDescriptor.getTag(index: Int): String {
-            return if (!isPolymorph) composeName(
-                currentTagOrNull.orEmpty(),
-                getConventionElementName(index, useConfigNamingConvention)
-            ) else getElementName(index)
+            val conventionName = getConventionElementName(index, useConfigNamingConvention)
+            return if (!isPolymorphic) composeName(currentTagOrNull.orEmpty(), conventionName) else conventionName
         }
 
         override fun decodeNotNullMark(): Boolean {
@@ -215,8 +213,7 @@ public sealed class Hocon(
 
         override fun beginStructure(descriptor: SerialDescriptor): CompositeDecoder =
             when {
-                // Polymorph should always be object-like I believe?
-                descriptor.kind.objLike -> ConfigReader(conf, isPolymorph = true)
+                descriptor.kind.objLike -> ConfigReader(conf, isPolymorphic = true)
                 else -> this
             }