Add links #10

The text does not include links. The page could be more accessible when everything that can be a link, is one.

Like words:

• Linux
• kernel
• Ubuntu
• GNOME
• desktop environment
• FreeDesktop
• SysTray
• API
• XDG Desktop Portals (and link to the specific standards and APIs)
• Linux kernel
• command line

I don't think the intended audience necessarily know these terms.

In the items you have actually links e.g. https://islinuxabout.xyz/apps/, but not in the text above.

@cassidyjames what do you think?