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

pezcumulus/client/relay-chain-inprocess-interface/src/lib.rs

@@ -109,12 +109,13 @@ impl RelayChainInterface for RelayChainInProcessInterface {
 	async fn header(&self, block_id: BlockId) -> RelayChainResult<Option<PHeader>> {
 		let hash = match block_id {
 			BlockId::Hash(hash) => hash,
-			BlockId::Number(num) =>
+			BlockId::Number(num) => {
 				if let Some(hash) = self.full_client.hash(num)? {
 					hash
 				} else {
 					return Ok(None);
-				},
+				}
+			},
 		};
 		let header = self.full_client.header(hash)?;