docs: 同步日常维护指南并补齐遗漏的板卡配置

mixly/boards/default_src/micropython/language/en.js

@@ -0,0 +1,9 @@
+import * as Mixly from 'mixly';
+import TEMPLATE from '../template/board-config-message.html';
+
+const { XML } = Mixly;
+
+export const MICROPYTHON_CONFIG_MESSAGE_BURN_SPEED = XML.render(TEMPLATE, {
+    title: 'Burn Speed',
+    message: 'To select the flashing speed, change the Burn Speed. This value will be used for flashing the code to the device. If you have issues while flashing the device at high speed, try to decrease this value. This could be due to the external serial-to-USB chip limitations.'
+});