[BUG] Collection of bugs in combo logic

[anoburn]

There are currently several bugs in the logic of the combo module (as mentioned on [Zulip](#KMK development > Combo behavior on key release).
For the test examples, I assume the default test layer from the combo unittests: [KC.A, KC.B, KC.C, KC.D, KC.E, KCMO, KC.F, KC.G] and the same general setup.

BUG 1

A small one: when match_coord=True and only a 0 remains for a combo (remaining = [0]), this will result in any(remaining) = False, triggering combos even though the 0-key has not been pressed. For example:

combos = [
    Chord((0, 1), KC.X, match_coord=True)
]

keyboard.test(
    'bug1',
    [
        (1, True),
        (1, False),
        t_after,
    ],
    [{KC.B}, {}],
)

The actual result is [{KC.X}, {}] because the 0 is not taken into consideration.

I've already fixed this one (see here, but hadn't opened a pull request so far because I was expecting a bigger rewrite for other things (see also the [Zulip post](#KMK development > Combo behavior on key release). I can still make a PR, if wished.

BUG 2

When two combos overlap and the first one is not completed, this will prohibit the second combo from triggering. For example:

combos = [
    Sequence((KC.A, KC.B, KC.C), KC.X),
    Sequence((KC.B, KC.D), KC.Y),
]

keyboard.test(
    'bug2',
    [
        (0, True), (0, False),
        t_within,
        (1, True), (1, False),
        t_within,
        (3, True), (3, False),
        t_after,
    ],
    [{KC.A}, {}, {KC.Y}, {}],
)

The actual result will be [{KC.A}, {}, {KC.B}, {}, {KC.D}, {}]

BUG 3

Combos don't trigger if typed too fast and another combo was still matching. For example:

combos.combos = [
    Chord((KC.A, KC.B), KC.X, timeout=3 * timeout),
    Chord((KC.A, KC.B, KC.C), KC.Y),
]
keyboard.test(
    'bug3',
    [
        (6, True),
        (7, True),
        (6, False),
        (7, False),
        t_after,
        (6, True),
        (7, True),
        (6, False),
        (7, False),
        3*t_after,
    ],
    [{KC.Z}, {}, {KC.Z}, {}]
)

The actual result are only the raw inputs, with no combos being activated {'A'}, {'A', 'B'}, {'B'}, {}, {'A'}, {'A', 'B'}, {'B'}, {}.
I guess one could argue this is intended behavior and is more of a feature request than a bug report, but this way combos are pretty much unusable when typing at higher speeds.