Implement the ability to work with `W` outside of `write`

I want for example instead of this

use stm32f1::stm32f103 as pac;
let periph = pac::Peripherals::take().unwrap();
let usart1 = periph.USART1;
// ...
usart1.cr1.write(|w| {
    w.ue().enabled();
    w.m().m9();
    w.pce().enabled();
    w.ps().even();
    w.te().enabled();
    w.tcie().enabled();
    w.re().disabled(); // <- First write
    w
});
// ...
usart1.cr1.write(|w| {
    w.ue().enabled();
    w.m().m9();
    w.pce().enabled();
    w.ps().even();
    w.te().enabled();
    w.tcie().enabled();
    w.re().enabled(); // <- Modified
    w
});
// ...
usart1.cr1.write(|w| {
    w.ue().enabled();
    w.m().m9();
    w.pce().enabled();
    w.ps().even();
    w.te().enabled();
    w.tcie().enabled();
    w.re().disabled(); // <- Modified
    w
});

to do so

use stm32f1::stm32f103 as pac;
let periph = pac::Peripherals::take().unwrap();
let usart1 = periph.USART1;
// ...
const USART_BASE_CFG: pac::usart1::cr1::W = pac::usart1::cr1::INITIAL_VALUE
    .ue().enabled()
    .m().m9()
    .pce().enabled()
    .ps().even()
    .te().enabled()
    .tcie().enabled()
    .re().disabled();
// ...
usart1.cr1.write(USART_BASE_CFG);
// ...
usart1.cr1.write(USART_BASE_CFG.re().enabled());
// ...
usart1.cr1.write(USART_BASE_CFG.re().disabled());

Or for example like this

let mut w = pac::usart1::cr1::INITIAL_VALUE;
w = w
   .ue().enabled()
   .m().m9()
   .pce().enabled()
   .ps().even()
   .te().enabled()
   .tcie().enabled()
   .re().disabled();
usart1.cr1.write(w);

Is it possible to change svd2rust to allow this?

The issue provides Rust examples of the desired register API, but names no file, test, or generator entry point. Trace the generated register writer API and its generator, then determine how reusable W values should behave outside write. Done means the examples can compile and the register behavior is covered by tests.