BlockId removal: refactor: HeaderBackend::header (#12874)

* BlockId removal: refactor: HeaderBackend::header

It changes the arguments of:
- `HeaderBackend::header`,
- `Client::header`,
- `PeersClient::header`
- `ChainApi::block_header`

methods from: `BlockId<Block>` to: `Block::Hash`

This PR is part of BlockId::Number refactoring analysis (paritytech/substrate#11292)

* non-trivial usages of haeder(block_id) refactored

This may required introduction of dedicated function:
header_for_block_num

* fmt

* fix

* doc fixed

* ".git/.scripts/fmt.sh"

* BlockId removal: refactor: HeaderBackend::expect_header

It changes the arguments of `HeaderBackend::expect_header` method from: `BlockId<Block>` to: `Block::Hash`

* ".git/.scripts/fmt.sh"

* readme updated

* ".git/.scripts/fmt.sh"

* fix

Co-authored-by: parity-processbot <>

substrate/client/sync-state-rpc/src/lib.rs

@@ -48,10 +48,7 @@ use jsonrpsee::{
 };
 use sc_client_api::StorageData;
 use sp_blockchain::HeaderBackend;
-use sp_runtime::{
-	generic::BlockId,
-	traits::{Block as BlockT, NumberFor},
-};
+use sp_runtime::traits::{Block as BlockT, NumberFor};
 use std::sync::Arc;
 
 type SharedAuthoritySet<TBl> =
@@ -164,7 +161,7 @@ where
 		let finalized_hash = self.client.info().finalized_hash;
 		let finalized_header = self
 			.client
-			.header(BlockId::Hash(finalized_hash))?
+			.header(finalized_hash)?
 			.ok_or_else(|| sp_blockchain::Error::MissingHeader(finalized_hash.to_string()))?;
 
 		let finalized_block_weight =