Run rustfmt on the code

Only one line changed. That's pretty good!

Author: Techcable

examples/pretty.rs

@@ -5,7 +5,6 @@ extern crate slog_json;
 
 use slog::Drain;
 
-
 fn main() {
     let drain = slog_json::Json::new(std::io::stdout())
         .set_pretty(true)