Add parent slot to getConfirmedBlock (#7038)

* Add parent slot to getConfirmedBlock

* Fix bad text-replace

* Use camelCase in getConfirmedBlock

client/src/rpc_request.rs

@@ -23,9 +23,11 @@ pub struct Response<T> {
 }
 
 #[derive(Debug, Default, PartialEq, Serialize)]
+#[serde(rename_all = "camelCase")]
 pub struct RpcConfirmedBlock {
     pub previous_blockhash: Hash,
     pub blockhash: Hash,
+    pub parent_slot: Slot,
     pub transactions: Vec<(Transaction, Option<RpcTransactionStatus>)>,
 }