style: Migrate to stable-only rustfmt configuration

- Remove nightly-only features from .rustfmt.toml and vendor/ss58-registry/rustfmt.toml
- Removed features: imports_granularity, wrap_comments, comment_width,
  reorder_impl_items, spaces_around_ranges, binop_separator,
  match_arm_blocks, trailing_semicolon, trailing_comma
- Format all 898 affected files with stable rustfmt
- Ensures long-term reliability without nightly toolchain dependency

bizinikiwi/client/consensus/manual-seal/src/seal_block.rs

@@ -96,8 +96,9 @@ pub async fn seal_block<B, BI, SC, C, E, TP, CIDP, P>(
 		// use the parent_hash supplied via `EngineCommand`
 		// or fetch the best_block.
 		let parent = match parent_hash {
-			Some(hash) =>
-				client.header(hash)?.ok_or_else(|| Error::BlockNotFound(format!("{}", hash)))?,
+			Some(hash) => {
+				client.header(hash)?.ok_or_else(|| Error::BlockNotFound(format!("{}", hash)))?
+			},
 			None => select_chain.best_chain().await?,
 		};