Update mkdocs.yml

Author: codebug8

mkdocs.yml

@@ -208,7 +208,7 @@ nav:
       - 6ULLPro-开发示例: 'Stage2-Components/NetworkingApplications/MQTT/6ULLPro-Example.md' 
       - MP157Pro-开发示例: 'Stage2-Components/NetworkingApplications/MQTT/MP157Pro-Example.md'
   - 设备驱动开发:
-    -NXP-GPIO子系统:
+    - NXP-GPIO子系统:
       - 6ULLPro-LED灯: 'Stage3-DeviceDriver/Nxp/IMX6ULL/Pro/01-leddriver.md'
       - 6ULLPro-按键: 'Stage3-DeviceDriver/Nxp/IMX6ULL/Pro/02-keydriver.md'
       - 6ULLPro-SR501:  'Stage3-DeviceDriver/Nxp/IMX6ULL/Pro/03-sr501driver.md'
@@ -238,7 +238,6 @@ nav:
       - 简述: 'Stage3-DeviceDriver/01-Introduction.md' 
       - MP157Pro-OLED: 'Stage3-DeviceDriver/St/STM32MP157/Pro/09-oleddriver.md'
       - MP157Pro-DAC模块: 'Stage3-DeviceDriver/St/STM32MP157/Pro/10-dacdriver.md'      
-
   - 系统开发: 
     - Git工具使用:
       - 简述: 'Stage4-System/01-Introduction.md'