If multiple sticky keys with quick release were nested, only the first one
was properly released. This fix makes sure all of them are released properly.
Fixes https://github.com/zmkfirmware/zmk/issues/1149
this makes LS(LEFT_CONTROL) work as if shift and control were both
pressed explicitly. Previously, the left shift would have been released
as soon as another key was pressed. The implicit behavior is useful in
case of LS(NUMBER_1) when rolling over to other keys.
Also see #361.
okke