[Core] Listing for `is_incremental` macro

### Link to the page(s) on docs.getdbt.com requiring updates

This page describes the `is_incremental` macro:
https://docs.getdbt.com/docs/build/incremental-models

It would be nice if this macro showed up in the listing of [dbt Jinja functions](https://docs.getdbt.com/reference/dbt-jinja-functions) similarly to the [`execute`](https://docs.getdbt.com/reference/dbt-jinja-functions/execute) macro.

### Tell us more about this update

I'd actually expect the same for these two as well:
- [`should_full_refresh`](https://docs.getdbt.com/reference/resource-configs/full_refresh)
- [`should_store_failures`](https://docs.getdbt.com/reference/resource-configs/store_failures)

### Reviewers/Stakeholders/SMEs

DB

### Related GitHub issues

_No response_

### Additional information

_No response_