std::fmt::Display implementation of Weekday does not honour width, alignment or fill

[horazont]

Summary

The Display implementation of Weekday uses Formatter::write_str, which doesn't honour width or alignment and fill.

Reproducer

use chrono::Weekday;

fn main() {
    println!("Expected result: <{:X>10}>", format!("{}", Weekday::Mon));
    println!("Actual result: <{:X>10}>", Weekday::Mon);
}

(Playground)

Expected result

<XXXXXXXMon>

Actual result

<Mon>

[horazont]

Looking further, seems like the easy way out is to use Formatter::pad instead of write_str.

[djc]

Happy to review a PR for this!

[horazont]

There you go: #1621