[docs] Update changelog summary for semantic_text ELSER on EIS default (elastic#137339)

Author: leemthompo

docs/changelog/134708.yaml

@@ -1,5 +1,5 @@
 pr: 134708
-summary: Default `semantic_text` fields to ELSER on EIS when available
+summary: Default [semantic_text](/reference/elasticsearch/mapping-reference/semantic-text.md) fields to use [ELSER on EIS](docs-content://explore-analyze/elastic-inference/eis.md#elser-on-eis) when available
 area: Mapping
 type: enhancement
 issues: []