modals: Improve error when resolver returns null

Author: freya022

BotCommands-core/src/main/kotlin/io/github/freya022/botcommands/internal/modals/ModalHandlerInfo.kt

@@ -105,7 +105,7 @@ internal class ModalHandlerInfo internal constructor(
                     option.resolver.resolveSuspend(option, event, modalMapping).also { obj ->
                         // Technically not required, but provides additional info
                         requireUser(obj != null || option.isOptionalOrNullable) {
-                            "The parameter '${option.declaredName}' from $modalMapping and value ${modalMapping.valueAsString} is required but was resolved to null"
+                            "The parameter '${option.declaredName}' is required but was resolved to null (from a ${modalMapping.type.name} with ID '${modalMapping.customId}' and value ${modalMapping.valueAsString})"
                         }
                     }
                 }

BotCommands-core/src/main/kotlin/io/github/freya022/botcommands/internal/modals/utils/ModalMappings.kt

@@ -10,7 +10,8 @@ internal val ModalInteractionEvent.allValuesAsString: String
 internal val ModalMapping.valueAsString: String
     get() = when (type) {
         STRING_SELECT, CHECKBOX_GROUP -> asStringList.map { "'${it}'" }.toString()
-        TEXT_INPUT, RADIO_GROUP -> if (asOptionalString == null) "<null>" else "'${asString}'"
+        TEXT_INPUT -> if (asOptionalString == null) "<empty>" else "'${asString}'"
+        RADIO_GROUP -> if (asOptionalString == null) "<none>" else "'${asString}'"
         CHANNEL_SELECT, ROLE_SELECT, USER_SELECT, MENTIONABLE_SELECT -> asLongList.toString()
         FILE_UPLOAD -> asAttachmentList.map { "${it.fileName} (${it.contentType}, ${it.size} B)" }.toString()
         CHECKBOX -> "<$asBoolean>"