Astro endpoints broken and typed rules not supported

### Your environment n/a ### Describe the bug The naming convention rule for Astro endpoints was misconfigured (sorry, my mistake) as it used `selector: 'function'` even though it should be `variable`. Also, type checked rules don't work as we have not set project for virtual files created by `eslint-plugin-astro`. ### Project eslint-config-sheriff ### Minimal reproduction _No response_ ### Steps to reproduce _No response_ ### Logs ```shell ``` ### Code of Conduct - [x] I agree to follow this project's [Code of Conduct](https://github.com/AndreaPontrandolfo/sheriff/blob/master/CODE_OF_CONDUCT.md) - [x] I have read the [Contributing Guidelines on Issues](https://github.com/AndreaPontrandolfo/sheriff/blob/master/CONTRIBUTING.md#opening-a-new-issue). ### I will submit a PR - [x] I'd be willing to submit a PR for this issue.