chore: Add rustfmt config

Readme.md

@@ -7,7 +7,7 @@ Displays different C-ITS receive-only use cases for cheap.
 ### Toolchain Installation
 Install the toolchain, targe and tools like this:
 
-```
+```shell
 rustup toolchain install nightly --component rust-src
 rustup target add riscv32imac-unknown-none-elf
 
@@ -18,6 +18,11 @@ cargo install espflash --locked
 
 (Project was setup using esp-generate with the options `--chip esp32c5 -o esp32c5-wroom-1-psram -o alloc -o log -o unstable-hal -o wifi -o esp-backtrace -o embassy`.)
 
+To use the proper rustfmt features, enable the nightly toolchain:
+```shell
+rustup component add --toolchain nightly rustfmt
+```
+
 ### Build and Flash
 Connect your ESP32-C5 and run:
 

rustfmt.toml

@@ -0,0 +1,6 @@
+unstable_features = true
+format_code_in_doc_comments = true
+
+group_imports = "StdExternalCrate"
+imports_granularity = "Module"
+imports_layout = "HorizontalVertical"