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/primitives/utility/src/tests/swap_first.rs

@@ -538,12 +538,14 @@ pub mod mock {
 			a: &Asset,
 		) -> core::result::Result<(AssetId, Balance), xcm_executor::traits::Error> {
 			match a {
-				Asset { fun: Fungible(amount), id: AssetId(inner_location) } =>
+				Asset { fun: Fungible(amount), id: AssetId(inner_location) } => {
 					match inner_location.unpack() {
-						(0, [Junction::GeneralIndex(id)]) =>
-							Ok(((*id).try_into().unwrap(), *amount)),
+						(0, [Junction::GeneralIndex(id)]) => {
+							Ok(((*id).try_into().unwrap(), *amount))
+						},
 						_ => Err(xcm_executor::traits::Error::AssetNotHandled),
-					},
+					}
+				},
 				_ => Err(xcm_executor::traits::Error::AssetNotHandled),
 			}
 		}