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/tracing/src/block/mod.rs

@@ -217,10 +217,9 @@ where
 	pub fn trace_block(&self) -> TraceBlockResult<TraceBlockResponse> {
 		tracing::debug!(target: "state_tracing", "Tracing block: {}", self.block);
 		// Prepare the block
-		let id = BlockId::Hash(self.block);
 		let mut header = self
 			.client
-			.header(id)
+			.header(self.block)
 			.map_err(Error::InvalidBlockId)?
 			.ok_or_else(|| Error::MissingBlockComponent("Header not found".to_string()))?;
 		let extrinsics = self
@@ -298,7 +297,7 @@ where
 			})
 		} else {
 			TraceBlockResponse::BlockTrace(BlockTrace {
-				block_hash: block_id_as_string(id),
+				block_hash: block_id_as_string(BlockId::<Block>::Hash(self.block)),
 				parent_hash: block_id_as_string(parent_id),
 				tracing_targets: targets.to_string(),
 				storage_keys: self.storage_keys.clone().unwrap_or_default(),