style: cargo fmt the assertion 2b086b2 added

2b086b2 landed an assert_eq! that rustfmt wraps, and `cargo fmt --all --check`
is the first step of the host CI job -- so every step after it was SKIPPED,
including the test run. PR #101 inherited the red through its merge commit
while its own file is formatted correctly.

Run the formatter before committing, not after CI says so.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FC2jVn8Au7E9JPkw6bwXXH

crates/improvise-io/src/persistence/parse.rs

@@ -1098,7 +1098,11 @@ mod parser_edge_cases {
         let m = parse_md(text).unwrap();
         let cat = m.model.category("Type").unwrap();
         let item_names: Vec<&str> = cat.items.values().map(|i| i.name.as_str()).collect();
-        assert_eq!(item_names, ["A", "B"], "the merge dropped a section's items");
+        assert_eq!(
+            item_names,
+            ["A", "B"],
+            "the merge dropped a section's items"
+        );
     }
 
     #[test]