Cargo.toml: split feature into many lines

For readability and better diffs.

Author: benma

src/rust/bitbox02-rust-c/Cargo.toml

@@ -73,7 +73,16 @@ platform-bitbox02 = []
 platform-bitbox02plus = ["util/sha2", "bitbox02-noise", "bitbox02-rust"]
 
 bootloader = []
-firmware = ["bitbox02-rust", "bitbox02-rust/firmware", "bitbox02", "bitbox02-noise", "util/sha2", "util/firmware", "der", "bitbox-aes"]
+firmware = [
+  "bitbox02-rust",
+  "bitbox02-rust/firmware",
+  "bitbox02",
+  "bitbox02-noise",
+  "util/sha2",
+  "util/firmware",
+  "der",
+  "bitbox-aes",
+]
 
 # Only to be enabled in Rust unit tests.
 testing = ["bitbox02-rust/testing", "bitbox02/testing"]