update changelog

Author: markjhoy

docs/changelog/128854.yaml

@@ -1,12 +1,11 @@
 pr: 128854
-summary: Mark Token Pruning for Sparse Vector as GA
+summary: Mark token pruning for sparse vector as GA
 area: Relevance
 type: docs
 issues: []
 highlight:
   title: Mark Token Pruning for Sparse Vector as GA
   body: |-
-    A docs change to remove the [preview] labels for the token pruning
-    configuration items for the Sparse Vector query as we get ready to put
-    these into GA.
+    Token pruning for sparse_vector queries has been live since 8.13 as tech preview.
+    As of 8.19.0 and 9.1.0, this is now generally available.
   notable: true