Add links to examples

[idg10]

In at least some of these examples, I understand these patterns are used in Microsoft frameworks, e.g.: https://github.com/davidfowl/DotNetCodingPatterns/blob/f77b54f105d90078359d006796193c56e406ce2e/1.md?plain=1#L11

I would find it really helpful if these cases could have links to one or more examples. Seeing a pattern described purely in the abstract can be tricky to grasp. If we can see a specific example of where it has been used, that can make it a lot easier to grasp the rationale.