Add to changelog.

Author: qwandor

CHANGELOG.md

@@ -2,13 +2,19 @@
 
 ## Unreleased
 
-- add support for nRF52805
+### New features
+
+- Added support for nRF52805 ([#422]).
+- Added implementation of RTIC `Monotonic` for RTC and TIMER, behind new `monotonic` feature ([#427]).
+
+[#422]: https://github.com/nrf-rs/nrf-hal/pull/422
+[#427]: https://github.com/nrf-rs/nrf-hal/pull/427
 
 ## [0.17.1]
 
 ### New features
 
-- Implemented `embedded-hal` 1.0 `I2c` trait for `Twi` and `Twim` [#440].
+- Implemented `embedded-hal` 1.0 `I2c` trait for `Twi` and `Twim` ([#440]).
 
 [#440]: https://github.com/nrf-rs/nrf-hal/pull/440