[#79B53D34FC61E5CE15C0301A400D425D159B48A9]
Set the fragment.
url_base& set_encoded_fragment(pct_string_view s);
This function sets the fragment to the specified string, which may contain percent-escapes and which may be empty. An empty fragment is distinct from having no fragment. Escapes in the string are preserved, and reserved characters in the string are percent-escaped in the result.
assert( url("?first=john&last=doe" ).set_encoded_fragment( "john%2Ddoe" ).fragment() == "john-doe" );
this->has_fragment() == true && this->fragment() == decode_view( s )
Linear in `this->size() + s.size()`.
Strong guarantee. Calls to allocate may throw. Exceptions thrown on invalid input.
fragment = *( pchar / "/" / "?" )