Unexpected slash "\=>"

[katopz]

at https://github.com/wasmflow/node-to-rust/blob/master/book/chapters/chapter-15-closures.adoc#basic-closure-syntax

let closure = () \=> {
  console.log("Hi! I'm in a closure");
};
closure();

has weird \=> for some reason and it's appear all over the book. Not sure what it was. You can assign to me if it's a bug I will take a look.

Cheers