Rec28 is too free with slashes

[VladimirAlexiev]

Rec28 has this value:

• https://service.unece.org/trade/uncefact/vocabulary/rec28/#Timber/log_carrier

But slashes are supposed to separate URL path components and should not be used freely in the fragment part.
That slash could be replaced with an underscore, just like the space: #Timber_log_carrier.