Add missing tests

Author: lionel-

crates/oak_ide/tests/integration/find_references.rs

@@ -307,4 +307,9 @@ fn test_cross_package_references_via_library() {
         (script, range(use_start, use_start + 3)),
         (pkg_file, range(0, 3)),
     ]);
+
+    // Excluding the declaration drops the package definition `pkg_file`,
+    // leaving only the script use.
+    let refs = find_references(&db, script, offset(use_start), false);
+    assert_eq!(pairs(&refs), vec![(script, range(use_start, use_start + 3))]);
 }