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/network/availability-recovery/src/tests.rs

@@ -2499,8 +2499,8 @@ fn systematic_chunks_are_not_requested_again_in_regular_recovery() {
 					&mut virtual_overseer,
 					1,
 					|i| {
-						if (test_state.chunks.get(i).unwrap().index.0 as usize) <
-							test_state.systematic_threshold()
+						if (test_state.chunks.get(i).unwrap().index.0 as usize)
+							< test_state.systematic_threshold()
 						{
 							panic!("Already requested")
 						} else {