Function with_call_formal 

pub(crate) fn with_call_formal(
    formals: &str,
    call_formal: Option<&str>,
) -> String

Append a standalone wrapper’s CallAttribution::formal to its joined formals (#1613). The formal goes last: after ... and after any formal that follows the dots, so positional extras land in the dots and .call is matched by name only; a wrapper without other formals takes it alone.