link fixed

Author: bowenjw

docs/docs/fan-unit/index.mdx

@@ -95,7 +95,7 @@ import ThemedImage from '@theme/ThemedImage';
         </table>
 
         :::info
-        When using the standard Fan Unit only the [port A(left)](/fan-unit/GPIO#blade-connector) can be used for PWM
+        When using the standard Fan Unit only the [port A(left)](/fan-unit/gpio#blade-connector) can be used for PWM
         :::
 
     </TabItem>