Fix incorrect feature flag name in the doc

doc/user/discussions/index.md

@@ -526,14 +526,14 @@ To enable it:
 
 ```ruby
 # Instance-wide
-Feature.enable(:batched_suggestions)
+Feature.enable(:batch_suggestions)
 ```
 
 To disable it:
 
 ```ruby
 # Instance-wide
-Feature.disable(:batched_suggestions)
+Feature.disable(:batch_suggestions)
 ```
 
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