Fail to run when compiled with rust nightly

[andelf]

Clue:

• The firmware is loaded
• The PC is at panic_handler.
• mcause is 0x8000008e

See-also
5e5a0e0#commitcomment-139706558

[andelf]

@Merisy-Thing I finally figured out why.

I finally figured out the issue with the *.json target.

I previously used a *.json target successfully with another name. That created some confusion for me initially.

This time, I checked the sections using cargo objdump --release --example debug -- -s and all I found was a "not implemented" message in the .bss section. It seemed like the Rust compiler was complaining about an unrecognized target format.

A simple mistake in the JSON file name format. ‍🥲