clippy: remove useless_vec

This currently breaks CI in e.g. https://github.com/gitpatch-rs/gitpatch/actions/runs/20013661647/job/57387162629#step:5:70

Author: sourcefrog

src/ast.rs

@@ -299,16 +299,14 @@ mod tests {
             range_hint: "",
             lines: vec![],
         };
-        for (input, expected) in vec![
-            ("", None),
+        for (input, expected) in [("", None),
             (" ", None),
             ("  ", None),
             ("x", Some("x")),
             (" x", Some("x")),
             ("x ", Some("x ")),
             (" x ", Some("x ")),
-            ("  abc def ", Some("abc def ")),
-        ] {
+            ("  abc def ", Some("abc def "))] {
             h.range_hint = input;
             assert_eq!(h.hint(), expected);
         }