Update 04.analog.md

Changed the description, what to learn in this part

Author: kinkpunk

content/micropython-course/course/05.analog/04.analog.md

@@ -12,9 +12,8 @@ In this chapter, we will explore how to read analog signals using an **Analog-to
 Analog signals are used to represent phenomena in the real world, such as pressure, temperature or other physical quantities. Analog signals differ from digital ones as they can have an **infinite** number of possible values, whereas digital ones are **finite**. 
 
 You will learn the following in this chapter:
-- How to read a button,
-- how to turn on an LED,
-- how to make the Nano ESP32 perform a continuous action (placing it in a loop).
+- How to read an analog signal,
+- how to control output devices such as LED.
 
 ## Analog Signals