[DOCS] Update ES|QL generated docs to consistently use the applies_to metadata (elastic#128576)

- Add PREVIEW annotations to all preview functions
- Update docs generation logic to use annotations instead of preview boolean
* Changed stack: ga 9.1 to stack: coming in multiple places
  - Match.java: Updated the options parameter description
  - MultiMatch.java: Updated the options parameter description
  - ToLower.java: Reformatted parameter description and updated version annotation
  - ToUpper.java: Removed the appliesTo annotation entirely and reformatted parameter description

- updated applies_to annotations to specify both preview 9.0.0 and ga 9.1.0 lifecycle stages
- added version-specific documentation examples with applies_to markers for ga 9.1.0 features
- enhanced to_lower and to_upper functions to indicate support for multi-valued expressions in ga 9.1.0
- added version guards around function parameters and descriptions using applies_to syntax
- updated function parameter descriptions to indicate ga 9.1.0 availability for named parameters
- use detailedDescription + and fix match_phrase applies_to syntax
- strip inline applies_to from kibana docs
- update roundto, matchphrase lifecycles
-  fix match named params info
- various spatial functions are preview
- unsigned long is preview
- update qstr
- Update TO_LOWER/TO_UPPER parameter descriptions for clarity
- hide spatial functions per elastic#129839
- added `stack: ga 9.1.0` blocks to match_phrase.md and qstr.md examples
- simplified term.md version from `preview 9.0.0` to just `preview`
- added `applies_to = "stack: ga 9.1.0"` to matchphrase and querystring java annotations
- removed version `9.0.0` from term function annotation
- deleted unused `makeCallout()` and `appendLifeCycleAndVersion()` methods

Co-authored-by: elasticsearchmachine <[email protected]>
Co-authored-by: Liam Thompson <[email protected]>
Co-authored-by: Liam Thompson <[email protected]>
Co-authored-by: Nik Everett <[email protected]>

Author: 4 people