Document how to make use of & debug the example type checking?

**Do you want to request a _feature_ or report a _bug_?**

_feature_

**What is the current behavior?**

I have a [library I am trying to document](https://github.com/Docmaps-Project/docmaps/pull/34) using docs-ts, because it is a library of io-ts codecs. I have written examples for each of the core codecs and suddenly encounter an issue where `npx docs-ts` fails like that:

```
TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts" for /Users/eve/docmaps/packages/ts-sdk/docs/examples/index.ts
at new NodeError (node:internal/errors:399:5)
at Object.getFileProtocolModuleFormat [as file:] (node:internal/modules/esm/get_format:79:11)
at defaultGetFormat (node:internal/modules/esm/get_format:121:38)
[ ... omitted ... ]
code: 'ERR_UNKNOWN_FILE_EXTENSION'
}
```

It seems like docs-ts is doing some awesome footwork to prove that my examples actually compile or type check anyway. However I haven't found docs or other issues that reference this behavior. Could we get an explainer on this, or info in the docs? I need to write examples, auto checking is optional feature for me so I would also be happy turning it off if there is need.

Thanks very much!

**Which versions of docs-ts, and which browser and OS are affected by this issue? Did this work in previous versions of docs-ts?**

NodeJS 18.14.0, macos 13.3, docs-ts 0.7.2

Start by reproducing `npx docs-ts` with the reported `docs/examples/index.ts` example and inspect how the command checks TypeScript examples. Document why this type-checking step produces the `.ts` extension error, how to debug it, and whether it can be disabled; the work is done when these steps are clear to users.

Written by the indexing model from the issue text.