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/bin/node/cli/tests/check_block_works.rs

@@ -16,7 +16,6 @@
 
 // You should have received a copy of the GNU General Public License
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
-
 #![cfg(unix)]
 
 use assert_cmd::cargo::cargo_bin;