prelude: add RCC to prelude

Author: astapleton

src/prelude.rs

@@ -1,5 +1,6 @@
 //! Prelude
 
 pub use crate::pwr::PwrExt as _stm32h5xx_hal_pwr_PwrExt;
+pub use crate::rcc::RccExt as _stm32h5xx_hal_rcc_RccExt;
 
 pub use fugit::{ExtU32 as _, RateExtU32 as _};