Add CasePathsCore usage example

[klaaspieter]

I was looking for an explanation on how to use CasePathsCore and happened to found it in the CasePathable documentation comment.

Before I found it though I wasn't aware that CasePathable was the protocol the macro synthesized conformance for. This moves the information to a place that is easier to find. Although maybe it should even be in a CasePathsCore README?

[stephencelis]

I might not be understanding the motivation behind this PR. The docs you added appear to come straight from the CasePathable protocol documentation.

Can you clarify the problem you were having? I'm not sure I understand the motivation behind "how to use CasePathsCore". Did you encounter the module name when adding CasePaths to an Xcode project and wanted to understand the difference between CasePathsCore and CasePaths? Or did you find CasePathsCore a different way?

If it's a question of documenting the modules for installation, we recently added this to our SharingGRDB project: https://github.com/pointfreeco/sharing-grdb/pull/49/files

Would such a tip have helped you here?

[klaaspieter]

Yeah, such a tip would help. I was basically looking for how to use CasePathsCore without the CasePathable macro and I had to go hunting for what the macro actually did to know that I was looking for the CasePathable protocol and it's documentation. In other words I think if you're coming to this library without any knowledge about how it works it's difficult to find the necessary information to use it without the macro.

You're right that my PR merely lifts the existing documentation to a place that I think is easier to find. I was expecting this (or similar) information to be in the CasePathsCore README but decided to update the documentation instead because that already exists 🤷.