correct a tikv config name (#5401) (#5430)

tikv-configuration-file.md

@@ -273,7 +273,7 @@ Configuration items related to storage
 + Note: The TTL feature is only available for the RawKV interface for now. You can only configure this feature when creating a new cluster because TTL uses different data formats in the storage layer. If you modify this item on an existing cluster, TiKV reports errors when it starts.
 + Default value: `false`
 
-### `ttl-poll-check-interval`
+### `ttl-check-poll-interval`
 
 + The interval of checking data to reclaim physical spaces. If data reaches its TTL, TiKV forcibly reclaims its physical space during the check.
 + Default value: `"12h"`