[DOCS][8.19] Promote ESQL search functions to GA in the docs

- removed `preview = true` from java function annotations for full-text search functions
- generated updates to asciidoc and kibana docs
- 8.x equivalent of elastic#129786

Author: leemthompo

docs/reference/esql/esql-limitations.asciidoc

@@ -106,8 +106,7 @@ is currently experimental.
 [[esql-limitations-full-text-search]]
 === Full-text search
 
-experimental:[] {esql}'s support for <<esql-search-functions,full-text search>>
-is currently in Technical Preview. One limitation of full-text search is that
+One limitation of <<esql-search-functions,full-text search>> is that
 it is necessary to use the search function, like <<esql-match>>, in a <<esql-where>> command
 directly after the <<esql-from>> source command, or close enough to it.
 Otherwise, the query will fail with a validation error.

docs/reference/esql/functions/kibana/definition/kql.json

@@ -16,7 +16,7 @@ Boolean operators for comparing against one or multiple expressions.
 * <<esql-in-operator>>
 * <<esql-like-operator>>
 * <<esql-rlike-operator>>
-* experimental:[] <<esql-search-operators>>
+* <<esql-search-operators>>
 // end::op_list[]
 
 include::binary.asciidoc[]