Improvements to the Intervals query page

### Type of issue

Other

### What documentation page is affected

https://www.elastic.co/docs/reference/query-languages/query-dsl/query-dsl-intervals-query

### What happened?

## Description
We’ve received user feedback that is generally positive, but includes a few actionable improvement ideas.

## Feedback summary

What's working:
- Clear definition at the top for newer users.
- Clear parameter list (type, description, required/optional) — keep this consistent.

What could be improved:
- Add a runnable example (e.g., an embedded interactive example or integration with a tool like Console or a code playground) to let users run the query and view sample responses/documents.
- Helpful links to introductory concepts (like analyzer). Consider adding more contextual links if available.
- Performance warnings (wildcards) are useful. Ensure these are consistently included in other query docs as well.
- Having both simple and complex examples is appreciated. Check whether we can expand with one additional “advanced” use case.

### Additional info

_No response_