message: white_check_mark: improved test coverage
  Tests for parse_error.109 were missing.
diff: @@ -272,6 +272,20 @@ TEST_CASE("JSON pointers")
  CHECK_THROWS_AS(j["/one"_json_pointer] = 1, json::parse_error);
  CHECK_THROWS_WITH(j["/one"_json_pointer] = 1,
  "[json.exception.parse_error.109] parse error: array index 'one' is not a number");
  + CHECK_THROWS_AS(j_const["/one"_json_pointer] == 1, json::parse_error);
  + CHECK_THROWS_WITH(j_const["/one"_json_pointer] == 1,
  + "[json.exception.parse_error.109] parse error: array index 'one' is not a number");
  +
  + CHECK_THROWS_AS(j.at("/one"_json_pointer) = 1, json::parse_error);
  + CHECK_THROWS_WITH(j.at("/one"_json_pointer) = 1,
  + "[json.exception.parse_error.109] parse error: array index 'one' is not a number");
  + CHECK_THROWS_AS(j_const.at("/one"_json_pointer) == 1, json::parse_error);
  + CHECK_THROWS_WITH(j_const.at("/one"_json_pointer) == 1,
  + "[json.exception.parse_error.109] parse error: array index 'one' is not a number");
  +
  + CHECK_THROWS_AS(json({{"/list/0", 1}, {"/list/1", 2}, {"/list/three", 3}}).unflatten(), json::parse_error);
  + CHECK_THROWS_WITH(json({{"/list/0", 1}, {"/list/1", 2}, {"/list/three", 3}}).unflatten(),
  + "[json.exception.parse_error.109] parse error: array index 'three' is not a number");
  // assign to "-"
  j["/-"_json_pointer] = 99;
  