using-in-frontend.md doc fix: add argv: []

[mathieucaroff]

this was necessary to get compilation with nearley 2.19.1 to work
-- at least when run in node.

Without it here's what I get:

./node_modules/nearley/lib/compile.js:37
                        opts.args[0] ? require('path').dirname(opts.args[0]) : process.cwd(),
                                 ^
TypeError: Cannot read property '0' of undefined

[kach]

Good catch. Could you rebuild the docs? That's why Travis is failing.

[abitrolly]

@mathieucaroff you can rebuild the docs with docker using this command.

docker run -v "$(pwd)":"/app" -w "/app/docs" -it --rm node bash -c "npm install && npm run make"