use HINT_PREFIX constant instead of hard-coded value
@@ -241,7 +241,7 @@ fn parse_param(mut input: &str, strict: bool) -> Result<Param, Cow<'static, str>
// Then, optional hint
let mut hint = None;
- if input.starts_with(':') {
+ if input.starts_with(HINT_PREFIX) {
// skip the prefix
input = &input[HINT_PREFIX.len()..];
