Fix vernac classification of `Fail Instance`
Fix vernac classification of `Fail Instance`

AFAIK `Fail Instance` cannot open a goal.

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