* Move to `DEVICE_DT_INST_DEFINE` everywhere.

See: https://docs.zephyrproject.org/2.5.0/releases/release-notes-2.5.html#deprecated-in-this-release
PR: https://github.com/zmkfirmware/zmk/pull/736

A hold-tap timer event would be triggered too soon if the hold-tap
was delayed for longer than its tapping-term. This may cause
accidental hold behavior when the correct behavior would be tap.

By queuing the timer event instead of executing it immediately,
other delayed events get a chance to be processed properly.

Quick release for sticky keys failed for non-layer keys. The sticky key
was released just before the key that was supposed to be modified was
handled.

The issue was caused by an error in the sticky key logic, which released
the sticky key before handling the key up event.

Fixes #696.

A hold-tap trigger was missing in the scenario where a hold-tap behavior
was queued for a while and it's timer should've run out.

This is an improvement on retro-tap, solving the 'flashing hold' issue
users people experience.

When the tapping-term expires, the hold key is normally pressed. When
retro-tap is enabled, this is undesirable; only an interrupted hold-tap
should trigger the hold behavior.

This change disables the hold behavior for the 'STATUS_HOLD_TIMER'
state when retro-tap is enabled, and makes sure the
'STATUS_HOLD_INTERRUPT' state will be triggered when appropriate.