add kdocs for the config of startup

startup/launcher/src/commonMain/kotlin/Config.kt

@@ -3,6 +3,19 @@ package dev.inmo.micro_utils.startup.launcher
 import dev.inmo.micro_utils.startup.plugin.StartPlugin
 import kotlinx.serialization.Serializable
 
+/**
+ * Contains just [List] of [StartPlugin]s. In json this config should look like:
+ *
+ * ```json
+ * {
+ *     "plugins": [
+ *         "dev.inmo.micro_utils.startup.launcher.HelloWorldPlugin"
+ *     ]
+ * }
+ * ```
+ *
+ * In the sample above [HelloWorldPlugin] will be loaded during startup of application
+ */
 @Serializable
 data class Config(
     val plugins: List<StartPlugin>