Update README.md (#54)

* Update README.md

* Apply suggestions from code review

Co-authored-by: Andre Richter <andre-richter@users.noreply.github.com>

README.md

@@ -117,7 +117,7 @@ Since the kernel developed in the tutorials runs on the real hardware, it is hig
 get a USB serial debug cable to get the full experience. The cable also powers the Raspberry once
 you connect it, so you don't need extra power over the dedicated power-USB.
 
-- I use a bunch of [these serial cables].
+- You can find USB-to-serial cables that should work right away at [\[1\]] [\[2\]].
 - You connect it to the GPIO pins `14/15` as shown below.
 - [Tutorial 6](06_drivers_gpio_uart) is the first where you can use it. Check it out for
   instructions on how to prepare the SD card to boot your self-made kernel from it.
@@ -128,7 +128,8 @@ you connect it, so you don't need extra power over the dedicated power-USB.
 
 ![UART wiring diagram](doc/wiring.png)
 
-[these serial cables]: https://www.amazon.de/dp/B0757FQ5CX/ref=cm_sw_r_tw_dp_U_x_ozGRDbVTJAG4Q
+[\[1\]]: https://www.amazon.de/dp/B0757FQ5CX/ref=cm_sw_r_tw_dp_U_x_ozGRDbVTJAG4Q
+[\[2\]]: https://www.adafruit.com/product/954
 
 ## 🙌 Acknowledgements