Add changelog for Snowball upgrade

Author: cbuescher

docs/changelog/114146.yaml

@@ -0,0 +1,20 @@
+pr: 114146 
+summary: Snowball stemmers have been upgraded 
+area: Analysis
+type: breaking
+issues: []
+breaking:
+ title: Snowball stemmers have been upgraded
+ area: Analysis
+ details: >-
+ Lucene 10 ships with an upgrade of its Snowball stemmers. 
+ For details see https://github.com/apache/lucene/issues/13209. Users using
+ Snowball stemmers that are experiencing changes in search behaviour on 
+ existing data are advised to reindex.
+ impact: >-
+ The upgrade should generally provide improved stemming results. Small changes
+ in token analysis can lead to mismatches with previously index data, so
+ existing indices using Snowball stemmers as part of their analysis chain
+ should be reindexed.
+ notable: false
+