Render ref of Nordic crosscountry pistes

[ppete2]

Like it's already done for downhill pistes, please also render a ref number of nordic pistes. For example if you open map at https://slopes.waymarkedtrails.org/#?map=15!47.7254!14.3218 there're several nordic routes. Not only with different colour-tag, but also with a different ref-Tag. Please render the numbers (e.g. "RW5") inside the colored circle markers of a route.