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/pezframe/benchmarking/src/v1.rs

@@ -923,7 +923,7 @@ macro_rules! impl_bench_name_tests {
 // Every variant must implement [`BenchmarkingSetup`].
 //
 // ```nocompile
-// 
+//
 // struct Transfer;
 // impl BenchmarkingSetup for Transfer { ... }
 //