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/client/chain-spec/src/json_patch.rs

@@ -33,10 +33,11 @@ use serde_json::Value;
 /// * `b` - The JSON object to merge with `a`.
 pub fn merge(a: &mut Value, b: Value) {
 	match (a, b) {
-		(Value::Object(a), Value::Object(b)) =>
+		(Value::Object(a), Value::Object(b)) => {
 			for (k, v) in b {
 				merge(a.entry(k).or_insert(Value::Null), v);
-			},
+			}
+		},
 		(a, b) => *a = b,
 	};
 }