This copies the first line of the description of each command to just
under the syntax so that it's "in order", before the `Parameters`
section. That way if you are reading from top to bottom you see:
```
syntax
short description
parameter names and descriptions
long description
examples
```
I've also removed the `Description` section entirely if the description
was just one sentence. So in some cases that just isn't `long
description`.
This adds some docs to the top of `docs.csv-spec` and
`docs-IT_tests_only.csv-spec` telling folks not to add more stuff there
and instead put new examples into whatever files they line up with. It
also shifts some things out of the file to "prime the pump" on cleaning
it up.
* Break out 'Limitations' into separate page
* Add REST API docs
* Restructure commands, functions, and operators refs
* Add placeholder for getting started guide
* Group 'Syntax', 'Metafields', and 'MV fields' under 'Language'
* Add placeholder for Kibana page
* Add link from landing page
* Apply uniform formatting to ACOS, CASE, and DATE_PARSE function refs
* Reword default LIMIT
* Add support for COUNT(*)
* Move 'Commands' and 'Functions and operators' to individual pages
---------
Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>
