fix check errors (#460)

Signed-off-by: Ping Yu <yuping@pingcap.cn>

src/proto.rs

@@ -5,6 +5,7 @@
 
 pub use protos::*;
 
+#[allow(clippy::doc_lazy_continuation)]
 mod protos {
     include!("generated/mod.rs");
 }

src/transaction/requests.rs

@@ -904,7 +904,6 @@ impl Merge<kvrpcpb::UnsafeDestroyRangeResponse> for Collect {
 }
 
 #[cfg(test)]
-#[cfg_attr(feature = "protobuf-codec", allow(clippy::useless_conversion))]
 mod tests {
     use crate::common::Error::PessimisticLockError;
     use crate::common::Error::ResolveLockError;