fmt: Add dunmy use to avoid "unused variable" errors when no log is enabled.

stm32-metapac/Cargo.toml

@@ -9,16 +9,18 @@ resolver = "2"
 cortex-m = "0.7.2"
 cortex-m-rt = { version = "0.6.8", optional = true }
 
+# BEGIN BUILD DEPENDENCIES
+# These are removed when generating the pre-generated crate using the tool at gen/.
 [build-dependencies]
 regex = "1.4.6"
 chiptool = { git = "https://github.com/embassy-rs/chiptool", rev = "86b77165078065058098e981d49d2dd213b2feba" }
 serde = { version = "1.0.123", features = [ "derive" ]}
 serde_yaml = "0.8.15"
+# END BUILD DEPENDENCIES
 
 [features]
 rt = ["cortex-m-rt/device"]
 
-
 # BEGIN GENERATED FEATURES
 # Generated by gen_features.py. DO NOT EDIT.
 stm32f030c6 = []