Display caps lock indicator in secure input

[ecton]

I'm uncertain if we can query the caps lock key status from winit, but we should show an indicator when masking is asctive if the caps lock key is pressed.

[Plecra]

We need winit to tell us about the caps lock state, really. It doesn't look like they expose the API yet, and its internally tracked in xkb state that we can't read.

They've got an implementation to check caps state on windows and linux, supported on both wayland and X. It just needs to be added to public API

[ecton]

Thank you for investigating how all that works!