[ML] Make categorize_text aggregation GA (#88600)

Removes the experimental tag from the categorize_text aggregation.

docs/changelog/88600.yaml

@@ -0,0 +1,10 @@
+pr: 88600
+summary: Make `categorize_text` aggregation GA
+area: Machine Learning
+type: feature
+issues: []
+highlight:
+  title: Make `categorize_text` aggregation GA
+  body: The `categorize_text` aggregation has been moved from
+        technical preview to general availability.
+  notable: true

docs/reference/aggregations/bucket/categorize-text-aggregation.asciidoc

@@ -4,8 +4,6 @@
 <titleabbrev>Categorize text</titleabbrev>
 ++++
 
-experimental::[]
-
 A multi-bucket aggregation that groups semi-structured text into buckets. Each `text` field is re-analyzed
 using a custom analyzer. The resulting tokens are then categorized creating buckets of similarly formatted
 text values. This aggregation works best with machine generated text like system logs. Only the first 100 analyzed