Make GrandpaBlockImport public (#6068)

substrate/client/finality-grandpa/src/lib.rs

@@ -118,6 +118,7 @@ mod voting_rule;
 
 pub use authorities::SharedAuthoritySet;
 pub use finality_proof::{FinalityProofProvider, StorageAndProofProvider};
+pub use import::GrandpaBlockImport;
 pub use justification::GrandpaJustification;
 pub use light_import::light_block_import;
 pub use voting_rule::{
@@ -127,7 +128,6 @@ pub use finality_grandpa::voter::report;
 
 use aux_schema::PersistentData;
 use environment::{Environment, VoterSetState};
-use import::GrandpaBlockImport;
 use until_imported::UntilGlobalMessageBlocksImported;
 use communication::{NetworkBridge, Network as NetworkT};
 use sp_finality_grandpa::{AuthorityList, AuthorityPair, AuthoritySignature, SetId};