Merge pull request #634 from kattni/pico-guide-link

Add Pico guide to Pico page.

Author: kattni

_board/raspberry_pi_pico.md

@@ -45,7 +45,8 @@ While the RP2040 has lots of onboard RAM (264KB), it does not have built in FLAS
 * USB 1.1 controller and PHY, with host and device support
 * 8 PIO state machines
 
-[Click here to get started with your Pico!](https://raspberrypi.org/documentation/pico/getting-started/)
+[Click here for the Raspberry Pi documentation.](https://raspberrypi.org/documentation/pico/getting-started/)
+[Click here for Getting Started with Raspberry Pi Pico and CircuitPython.](https://learn.adafruit.com/getting-started-with-raspberry-pi-pico-circuitpython)
 
 ## Purchase
 * [Adafruit](https://www.adafruit.com/product/4883)