[embassy-rp] Enabling chrono feature while defmt feature is enabled yields a compilation error #5119
Description
Embassy RP version: 0.9
Currently, chrono doesn't support defmt yet, but I think when I had a project on v0.7, this had no issue. However, I upgraded and immediately noticed the compilation errors popping up.
The culprit is this line here: https://github.com/embassy-rs/embassy/blob/main/embassy-rp/src/rtc/filter.rs#L8
The DayOfWeek type is cfg'd to be either the internal or chrono type, so when you toggle on chrono, DateTimeFilter breaks because chrono's DayOfWeek version doesn't implement defmt::Format.
This is a bug, but to fix it means either removing the Format impl or adding a cfg_attr configuration that disables the impl if chrono feature is active. That might be a breaking change in either case, or a weird behaviour that could be surprising to end-users.