Add SelectDefaultValues (#881)

The DSL looks like this:
val message = channel.createMessage {
    actionRow {
        mentionableSelect("customId") {
            allowedValues = 0..5
            defaultUsers += userId
            defaultRoles += roleId
        }
    }
}

See discord/discord-api-docs#6442

common/build/generated/ksp/metadata/commonMain/kotlin/dev/kord/common/entity/SelectDefaultValueType.kt

@@ -0,0 +1,88 @@
+// THIS FILE IS AUTO-GENERATED, DO NOT EDIT!
+@file:Suppress(names = arrayOf("IncorrectFormatting", "ReplaceArrayOfWithLiteral",
+                "SpellCheckingInspection", "GrazieInspection"))
+
+package dev.kord.common.entity
+
+import kotlin.LazyThreadSafetyMode.PUBLICATION
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+
+/**
+ * See [SelectDefaultValueType]s in the
+ * [Discord Developer Documentation](https://discord.com/developers/docs/interactions/message-components#select-menu-object-select-default-value-structure).
+ */
+@Serializable(with = SelectDefaultValueType.Serializer::class)
+public sealed class SelectDefaultValueType(
+    /**
+     * The raw value used by Discord.
+     */
+    public val `value`: String,
+) {
+    final override fun equals(other: Any?): Boolean = this === other ||
+            (other is SelectDefaultValueType && this.value == other.value)
+
+    final override fun hashCode(): Int = value.hashCode()
+
+    final override fun toString(): String =
+            if (this is Unknown) "SelectDefaultValueType.Unknown(value=$value)"
+            else "SelectDefaultValueType.${this::class.simpleName}"
+
+    /**
+     * An unknown [SelectDefaultValueType].
+     *
+     * This is used as a fallback for [SelectDefaultValueType]s that haven't been added to Kord yet.
+     */
+    public class Unknown internal constructor(
+        `value`: String,
+    ) : SelectDefaultValueType(value)
+
+    public object User : SelectDefaultValueType("user")
+
+    public object Role : SelectDefaultValueType("role")
+
+    public object Channel : SelectDefaultValueType("channel")
+
+    internal object Serializer : KSerializer<SelectDefaultValueType> {
+        override val descriptor: SerialDescriptor =
+                PrimitiveSerialDescriptor("dev.kord.common.entity.SelectDefaultValueType",
+                PrimitiveKind.STRING)
+
+        override fun serialize(encoder: Encoder, `value`: SelectDefaultValueType) {
+            encoder.encodeString(value.value)
+        }
+
+        override fun deserialize(decoder: Decoder): SelectDefaultValueType =
+                from(decoder.decodeString())
+    }
+
+    public companion object {
+        /**
+         * A [List] of all known [SelectDefaultValueType]s.
+         */
+        public val entries: List<SelectDefaultValueType> by lazy(mode = PUBLICATION) {
+            listOf(
+                User,
+                Role,
+                Channel,
+            )
+        }
+
+
+        /**
+         * Returns an instance of [SelectDefaultValueType] with [SelectDefaultValueType.value] equal
+         * to the specified [value].
+         */
+        public fun from(`value`: String): SelectDefaultValueType = when (value) {
+            "user" -> User
+            "role" -> Role
+            "channel" -> Channel
+            else -> Unknown(value)
+        }
+    }
+}

common/src/commonMain/kotlin/entity/DiscordComponent.kt

@@ -80,6 +80,8 @@ public sealed class DiscordComponent {
     public abstract val components: Optional<List<DiscordComponent>>
     public abstract val options: Optional<List<DiscordSelectOption>>
     public abstract val placeholder: Optional<String>
+    @SerialName("default_values")
+    public abstract val defaultValues: Optional<List<DiscordSelectDefaultValue>>
     @SerialName("min_values")
     public abstract val minValues: OptionalInt
     @SerialName("max_values")
@@ -119,6 +121,8 @@ public data class DiscordChatComponent(
      override val components: Optional<List<DiscordComponent>> = Optional.Missing(),
      override val options: Optional<List<DiscordSelectOption>> = Optional.Missing(),
      override val placeholder: Optional<String> = Optional.Missing(),
+    @SerialName("default_values")
+    override val defaultValues: Optional<List<DiscordSelectDefaultValue>> = Optional.Missing(),
     @SerialName("min_values")
      override val minValues: OptionalInt = OptionalInt.Missing,
     @SerialName("max_values")
@@ -146,6 +150,8 @@ public data class DiscordTextInputComponent(
      override val components: Optional<List<DiscordComponent>> = Optional.Missing(),
      override val options: Optional<List<DiscordSelectOption>> = Optional.Missing(),
      override val placeholder: Optional<String> = Optional.Missing(),
+    @SerialName("default_values")
+    override val defaultValues: Optional<List<DiscordSelectDefaultValue>> = Optional.Missing(),
     @SerialName("min_values")
      override val minValues: OptionalInt = OptionalInt.Missing,
     @SerialName("max_values")

common/src/commonMain/kotlin/entity/DiscordSelectDefaultValue.kt

@@ -0,0 +1,22 @@
+@file:Generate(
+    STRING_KORD_ENUM, name = "SelectDefaultValueType", unknownConstructorWasPublic = false,
+    docUrl = "https://discord.com/developers/docs/interactions/message-components#select-menu-object-select-default-value-structure",
+    entries = [
+        Entry("User", stringValue = "user"),
+        Entry("Role", stringValue = "role"),
+        Entry("Channel", stringValue = "channel"),
+    ],
+)
+
+package dev.kord.common.entity
+
+import dev.kord.ksp.Generate
+import dev.kord.ksp.Generate.EntityType.STRING_KORD_ENUM
+import dev.kord.ksp.Generate.Entry
+import kotlinx.serialization.Serializable
+
+@Serializable
+public data class DiscordSelectDefaultValue(
+    val id: Snowflake,
+    val type: SelectDefaultValueType,
+)