Remove VtUnknown classification
Remove VtUnknown classification

That classification is going to disappear from Coq. However, I don't
understand why it was used here. Can you confirm that the command can
not open a proof?

ejgallego/coq,Matafou/coq,JasonGross/coq,Zimmi48/coq,gares/coq,SkySkimmer/coq,JasonGross/coq,gares/coq,gares/coq,Zimmi48/coq,SkySkimmer/coq,JasonGross/coq,gares/coq,gares/coq,Matafou/coq,ejgallego/coq,coq/coq,coq/coq,JasonGross/coq,silene/coq,ejgallego/coq,SkySkimmer/coq,silene/coq,coq/coq,SkySkimmer/coq,coq/coq,Zimmi48/coq,Zimmi48/coq,ejgallego/coq,Matafou/coq,silene/coq