Minor but confusing mistake in documentation on `fn write`
//! pub fn read(&self) -> R { .. }
//!
//! /// Writes to the register
-//! pub fn write<F>(&mut self, f: F)
+//! pub fn write<F>(&self, f: F)
//! where
//! F: FnOnce(&mut W) -> &mut W,
//! {
