Gitignore update for doc_grammar.
Gitignore update for doc_grammar.

ejgallego/coq,JasonGross/coq,Zimmi48/coq,JasonGross/coq,coq/coq,coq/coq,JasonGross/coq,coq/coq,ejgallego/coq,SkySkimmer/coq,coq/coq,JasonGross/coq,SkySkimmer/coq,Zimmi48/coq,SkySkimmer/coq,ejgallego/coq,Zimmi48/coq,ejgallego/coq,Zimmi48/coq,SkySkimmer/coq