Run ocamlformat on modified ml / mli files in pre-commit hook.
Run ocamlformat on modified ml / mli files in pre-commit hook.

Thanks to `.ocamlformat-ignore`, we can call ocamlformat blindly but
only the non-ignored files will be affected.

Co-Authored-By: Gaëtan Gilbert <26fa16609af92f7dd138c57814f0f88d569d969c@skyskimmer.net>

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