Prevent bogus repeated keypresses when reloading config

[WhyNotHugo]

When reloading the configuration, each time that a configuration applies to a keyboard, an additional bogus keypress is sent to clients.

This seems to happen due to handle_keyboard_group_leave updating the pressed keys, but handle_keyboard_group_enter not doing the reverse, so the state of pressed keys is inconsistent.

Extend handle_keyboard_group_enter to mirror
handle_keyboard_group_leave, ensure state is consistent and no spurious key events are sent.

[WhyNotHugo]

Actually, I copied this from handle_keyboard_group_leave thinking I'd need to invert some booleans or replace some bits, but it ended up being identical. I think I can refactor.

[WhyNotHugo]

I think that's tidier. The diff would have been smaller putting keyboard_group_refocus at the end, but that requires an additional forward declaration and didn't seem worth it.

[emersion]

I can't reproduce the bug. I run Sway with wev -f wl_keyboard & sleep 5; swaymsg reload, then focus the wev window and press some keys. The behavior is the same with or without this patch.

[WhyNotHugo]

The easiest reproducer is to just type swaymsg reload and press enter. The terminal will receive multiple Enter events.

I have an impression that having more input blocks affects this further, I have:

input type:keyboard {
  xkb_layout us
  xkb_variant intl
  xkb_numlock enable
}

input "13364:528:Keychron_Keychron_K1_Pro"                  xkb_options caps:escape,compose:ralt
input "13364:528:Keychron_Keychron_K1_Pro_Consumer_Control" xkb_options caps:escape,compose:ralt

# …

Can you try an equivalent configuration?

[emersion]

Yeah, no dice. Could you find a way to make these "bogus repeated keypresses" visible in a wev or WAYLAND_DEBUG log?

[WhyNotHugo]

I realise I forgot to link to the issue which includes the WAYLAND_DEBUG output: #8852