@InstantMuffin

Describe the problem

Trying to fix #1291 and to get a more general understanding of how the IDE works behind the scenes to maybe help out in the future, I found that README.md in the arduino-ide-extension folder seems to be quite outdated because it has a couple of dead links.

To reproduce

Click on a number of links in that document, for example the ones referencing the serial monitor are broken/not up to date.

Expected behavior

Links that work.
(I'm sorry I have to fill out this field.)

Arduino IDE version

"All of them"

Operating system

N/A

Operating system version

Additional context

No response

Issue checklist

• I searched for previous reports in the issue tracker
• I verified the problem still occurs when using the latest nightly build
• My report contains all necessary details