Tweak the warning for arbitrary term hints.
Tweak the warning for arbitrary term hints.

Fixes #11970.

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