[ESQL] Update in-product help (#155159)

## Summary

This PR updates the ESQL in-product help with the latest commands and
functions, and brings it in line with the ESQL documentation.

<img width="1180" alt="image"
src="https://user-images.githubusercontent.com/9715543/233131094-517e879b-2690-4014-999f-d0fbc9a8761b.png">

### Checklist

Delete any items that are not applicable to this PR.

- [x] Any text added follows [EUI's writing
guidelines](https://elastic.github.io/eui/#/guidelines/writing), uses
sentence case text and includes [i18n
support](https://github.com/elastic/kibana/blob/main/packages/kbn-i18n/README.md)
- [x] This renders correctly on smaller devices using a responsive
layout. (You can test this [in your
browser](https://www.browserstack.com/guide/responsive-testing-on-local-server))

### For maintainers

- [ ] This was checked for breaking API changes and was [labeled
appropriately](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

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Co-authored-by: Stratoula Kalafateli <[email protected]>
Co-authored-by: kibanamachine <[email protected]>
Co-authored-by: gchaps <[email protected]>