Fix hex prefix
@@ -456,7 +456,7 @@ impl FormatSpec {
Some(FormatType::Binary) => "0b",
Some(FormatType::Octal) => "0o",
Some(FormatType::HexLower) => "0x",
- Some(FormatType::HexUpper) => "0x",
+ Some(FormatType::HexUpper) => "0X",
_ => "",
}
} else {
