doc fixes for mcu 2
doc fixes for mcu 2

blynkkk/blynk-library,blynkkk/blynk-library,ivankravets/blynk-library,blynkkk/blynk-library,ivankravets/blynk-library,ivankravets/blynk-library,ivankravets/blynk-library,ivankravets/blynk-library,blynkkk/blynk-library,blynkkk/blynk-library