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

pezkuwi/node/subsystem-bench/src/lib/statement/test_state.rs

@@ -397,10 +397,12 @@ impl HandleNetworkMessage for TestState {
 						let position_in_group =
 							backing_group.iter().position(|v| *v == validator_index).unwrap();
 						match statement.unchecked_payload() {
-							CompactStatement::Seconded(_) =>
-								seconded_in_group.set(position_in_group, true),
-							CompactStatement::Valid(_) =>
-								validated_in_group.set(position_in_group, true),
+							CompactStatement::Seconded(_) => {
+								seconded_in_group.set(position_in_group, true)
+							},
+							CompactStatement::Valid(_) => {
+								validated_in_group.set(position_in_group, true)
+							},
 						}
 					}
 				}