[#D55D9AAD32CB7478DE5F7B7C04F4B4D0D8546EEC]
Normalize the URL fragment
url& normalize_fragment();
Applies Syntax-based normalization to the URL fragment.
Percent-encoding triplets are normalized to uppercase letters. Percent-encoded octets that correspond to unreserved characters are decoded.
Strong guarantee. Calls to allocate may throw.