Fix duplicate //! headers in board.rs, update @brief, add // comments to lib.rs pub mod

- Remove duplicate //! @file/@brief/@author/@date blocks from all 8 board.rs
- Update original @brief to consistent 'Board-level HAL helpers for the XXX driver'
- Add // comment above pub mod in all 7 lib.rs files
- All 8 drivers build, all 75 tests pass

drivers/0x03_button_rust/src/board.rs

@@ -1,5 +1,5 @@
 //! @file board.rs
-//! @brief Board-level initialisation helpers for the button demo
+//! @brief Board-level HAL helpers for the button driver
 //! @author Kevin Thomas
 //! @date 2025
 //!
@@ -25,11 +25,6 @@
 //! OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 //! SOFTWARE.
 
-//! @file board.rs
-//! @brief Board-level HAL helpers for the button driver
-//! @author Kevin Thomas
-//! @date 2025
-
 // Rate extension trait for .Hz() baud rate construction
 use fugit::RateExtU32;
 // Clock trait for accessing system clock frequency

drivers/0x03_button_rust/src/lib.rs

@@ -5,4 +5,5 @@
 
 #![no_std]
 
+// Button driver module
 pub mod button;