This adds a new ESLint rule to `eslint-plugin-next` to check that `next/script` components with inline content have the required `id` attribute.
Also adjusted the code example for inline scripts in the `next/script` docs, which were actually missing an `id` attribute.
And also updated the `next/scripts` integration test to also have the required `id` attribute.
Unsure about the required heading levels in the errors .md document (other examples have h1 and h4??)
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [x] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [x] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes
