Fix setoid_rewrite to raise proper errors
Fix setoid_rewrite to raise proper errors

when the rewrite lemma doesn't typecheck or does not
correspond to a relation.

gares/coq,maximedenes/coq,ppedrot/coq,ejgallego/coq,SkySkimmer/coq,coq/coq,maximedenes/coq,SkySkimmer/coq,maximedenes/coq,Matafou/coq,coq/coq,Matafou/coq,JasonGross/coq,ppedrot/coq,Zimmi48/coq,gares/coq,SkySkimmer/coq,Zimmi48/coq,letouzey/coq-wip,william-lawvere/coq,Zimmi48/coq,gares/coq,amintimany/coq,ejgallego/coq,ejgallego/coq,letouzey/coq-wip,Zimmi48/coq,Lionel-Rieg/coq,JasonGross/coq,coq/coq,Matafou/coq,maximedenes/coq,ejgallego/coq,Lionel-Rieg/coq,letouzey/coq-wip,JasonGross/coq,maximedenes/coq,ppedrot/coq,Ptival/coq,Lionel-Rieg/coq,ppedrot/coq,letouzey/coq-wip,amintimany/coq,gares/coq,silene/coq,coq/coq,william-lawvere/coq,amintimany/coq,gares/coq,JasonGross/coq,ppedrot/coq,Ptival/coq,silene/coq,letouzey/coq-wip,Ptival/coq,SkySkimmer/coq,william-lawvere/coq,silene/coq