[NTG-context] fake slant for definefallbackfamily

I can define fake slant for a font with \definefontfamily[mainface][rm][My Fancy Font][sl=features:slanted] How can I do it with \definefallbackfamily? According to https://wiki.contextgarden.net/index.php?title=Command/definefallbackfamily , the following should work, but it actually doesn't: \definefallbackfamily[mainface][rm][My Fancy Font][preset={range:chinese},sl=features:slanted] Besides, the wiki page lists an option `range=...` in the last bracket, but what's actually used is `preset=range:...`. Are they mistakes?