Break out ES|QL commands into single pages

[KOTungseth]

Type of issue

I can't find what I'm looking for

What documentation page is affected

https://www.elastic.co/docs/reference/query-languages/esql/esql-commands

Description

Users are unable to easily find documentation for specific ES|QL commands, such as the ENRICH command, because:

• All commands are grouped on single, long pages: Source commands and Processing commands.
• The content is difficult to scan and search, especially for less commonly used commands.
• There is duplication between the ES|QL Commands overview page and subsequent Source commands and Processing commands pages.

Proposed solution

To improve discoverability, usability, and maintainability of ES|QL command documentation:

1. Split command documentation into individual pages

• Each ES|QL command (e.g., FROM, WHERE, ENRICH, etc.) should have its own dedicated page.
• Pages should include:
• Syntax
• Parameters
• Examples
• Related commands (optional cross-links)

2. Consolidate and deduplicate overview content

• Keep a concise overview of all commands on the main ES|QL commands page.
• Remove redundant content that appears both in the overview and on individual command pages.

3. Update navigation and internal links

• Update the ES|QL left nav to list each individual command.
• Ensure all existing links to commands in the current long-form page are redirected or updated.

[leemthompo]

closed by elastic/elasticsearch#133073

follow-up work for functions to be scheduled with esql dev: #2656