lsp: use File_id.with_cache in lsp callbacks
lsp: use File_id.with_cache in lsp callbacks

dra27/merlin,the-lambda-church/merlin,dra27/merlin,rgrinberg/merlin,ocaml/merlin,rgrinberg/merlin,dra27/merlin,the-lambda-church/merlin,rgrinberg/merlin,rgrinberg/merlin,dra27/merlin,ocaml/merlin,ocaml/merlin,ocaml/merlin,the-lambda-church/merlin