Allow configuring show_nonprintable from PrettyPrinter

[acheronfail]

This PR allows crates using bat as a library to configure the show_nonprintable setting via the PrettyPrinter API.

Note that it is possible to use bat as a lib and configure this, but the workaround requires using bat's "inner" API which is discouraged by bat's documentation.

Current workaround:

let mut config = bat::config::Config::default();
config.show_nonprintable = true;
let assets = bat::assets::HighlightingAssets::from_binary();
let ctrl = bat::controller::Controller::new(&config, &assets);
let inp = bat::input::Input::from(bat::Input::from_bytes(&output));
ctrl.run(vec![inp]).unwrap();

Once this PR is merged, consumers will be able to do this:

bat::PrettyPrinter::new()
    .input_from_bytes(&output)
    .show_nonprintable(true)
    .print()
    .expect("Failed to print to STDOUT");

---

Something else noteworthy: if using bat as a library, if binary content is detected then the PrettyPrinter will print:

[bat warning]: Binary content from READER will not be printed to the terminal (but will be present if the output of 'bat' is piped). You can use 'bat -A' to show the binary file contents.

I'm not sure if this has been discussed previously, but I imagine it could cause some surprise for crates which depend on bat since the -A flag obviously isn't available, etc.

[Enselic]

Thank you! Looks good to me. Would you mind adding an entry about it to CHANGELOG.md please?

[acheronfail]

No worries at all! And I've added an entry to the changelog. 👍

[sharkdp]

Thank you

[sharkdp]

Something else noteworthy: if using bat as a library, if binary content is detected then the PrettyPrinter will print:

[bat warning]: Binary content from READER will not be printed to the terminal (but will be present if the output of 'bat' is piped). You can use 'bat -A' to show the binary file contents.

I don't think this has been discussed, no. I agree that this should be improved. The "content from READER" part isn't great either 😄. It would be good if you could open a new ticket for this. Thanks!

[acheronfail]

No worries, I've done so here: #2146