De-linkify domain reference to avoid spurious link check failure

[per1234]

The license information readme contains a reference to www.arduino.cc.

Text that looks like a domain is automatically linkified by common Markdown renderers (including the one used by GitHub for repository contents), converting this to a link to http://www.arduino.cc. The project infrastructure includes a check for broken links in the Markdown files. The markdown-link-check tool that provides this check is smart enough to also check these auto-linkified links.

When the http://www.arduino.cc URL is opened normally, the Arduino website simply redirects to https://www.arduino.cc (note the https scheme) and all is well. However, apparently due to some draconian security settings on the arduino.cc web infrastructure, when markdown-link-check attempts to load that URL, it fails spuriously with an HTTP 403 Forbidden response code:

https://github.com/arduino/serial-discovery/actions/runs/6781582756/job/18432149415#step:4:15

ERROR: 1 dead links found in ./README.md !
  [✖] http://www.arduino.cc/ → Status: 403
task: Failed to run task "markdown:check-links": exit status 1

This could be fixed by changing the www.arduino.cc text to something like [www.arduino.cc](https://www.arduino.cc). However, I don't think there was ever an intention to encourage the reader of the text to visit that domain. Rather, it was added as an alternative way of identifying the entity referred to as "ARDUINO SA". For this reason, I think the most appropriate solution to the spurious link check failure is to prevent the linkification of this text. This is done by injecting HTML comment tags at strategic locations in the text. These tags cause the text to no longer be recognized as a domain name by the auto-linkifying code of the markdown-link-check tool and the GitHub Flavored Markdown renderer both.