I started #558 to get the Discovery book UART example safe again. The hanges have landed here and I could successfully test this with the nightly stm32f3 crate.

To get this fix into the Discovery examples, I would like to ask all the crate maintainers for an update. From my point of view, this is the crate to start with. Could you please make a patch/maintainance release for the stm32f3 crate to get this started?