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/primitives/state-machine/src/trie_backend.rs

@@ -1015,8 +1015,8 @@ pub mod tests {
 			.storage_root(iter::once((&b"new-key"[..], Some(&b"new-value"[..]))), state_version);
 		assert!(!tx.drain().is_empty());
 		assert!(
-			new_root !=
-				test_trie(state_version, None, None)
+			new_root
+				!= test_trie(state_version, None, None)
 					.storage_root(iter::empty(), state_version)
 					.0
 		);