elasticsearch/docs/reference/esql/functions/README.md

The files in these subdirectories are generated by ESQL's test suite:
* `description` - description of each function scraped from `@FunctionInfo#description`
* `examples` - examples of each function scraped from `@FunctionInfo#examples`
* `parameters` - description of each function's parameters scraped from `@Param`
* `signature` - railroad diagram of the syntax to invoke each function
* `types` - a table of each combination of support type for each parameter. These are generated from tests.
* `layout` - a fully generated description for each function
* `kibana/definition` - function definitions for kibana's ESQL editor
* `kibana/docs` - the inline docs for kibana

Most functions can use the generated docs generated in the `layout` directory.
If we need something more custom for the function we can make a file in this
directory that can `include::` any parts of the files above.

To regenerate the files for a function run its tests using gradle:
```
./gradlew :x-pack:plugin:esql:test -Dtests.class='*SinTests'
```

To regenerate the files for all functions run all of ESQL's tests using gradle:
```
./gradlew :x-pack:plugin:esql:test
```