prefer_interpolation_to_compose_strings

Use interpolation to compose strings and values.

The analyzer produces this diagnostic when string literals and computed strings are being concatenated using the + operator, but string interpolation would achieve the same result.

The following code produces this diagnostic because the String s is concatenated with other strings using the + operator:

String f(String s) {
  return '(' + s + ')';
}

Use string interpolation:

String f(List<String> l) {
  return '(${l[0]}, ${l[1]})';
}