Fix deprecated syntax warning from vernacextend.mlp.
Fix deprecated syntax warning from vernacextend.mlp.

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