Wrong function codes in modbus.rs

[Ibens3C]

Hi,
in the modbus.rs file is pub enum FunctionCode, where the default Modbus function codes are defined.
I've noticed, that the codes were taken over from decimal format and are defined as hex. This seems to be wrong.
For example:

/// 0x15 Write Multiple Coils
WriteMultipleCoils = 0x15,

should be

/// 15 Write Multiple Coils
WriteMultipleCoils = 0x0F,