Remove needless third party requests (fonts.googleapis.com)

[UniqueActive]

Hello!

I am using the Rust Programming Language book to learn Rust and am a big fan, but I can't help but notice the needless third party request to fonts.google.com, even in the local version of the book that comes through rustup.

To me this is an easily avoidable privacy intrusion, so I would be very happy to see this changed in the future. I do not want my computer to send a request to Google every time I am learning Rust, especially if it is easy to avoid by various means such as

1. Including the fonts with the local version of the book
2. Serving the fonts through your own servers
3. Simply not using them, it looks absolutely fine without them.

As it stands, Google fonts are a convenience feature that just furthers Google's omnipresence and omniscience and comes at a needless cost to user privacy and data traffic.

Thank you in advance!

[UniqueActive]

https://google-webfonts-helper.herokuapp.com/fonts

Here is an example of a project created to enable simple self-hosting of Google fonts. This would be an easy, small and good step for a less centralized internet. :)

[carols10cents]

Hi, we use mdbook, so this would need to be fixed with them. They already have an issue for this: rust-lang/mdBook#847

Thanks!