Light Counter sample code incorrect

[Jaqster]

Incorrect sample code for the Light Counter project - https://github.com/Microsoft/pxt-adafruit/blob/master/docs/examples/counter.md

Reported by a customer:
The sample code for the counter counts 0 1 2 3 4 5 6 7 8 9 00 01 02 03 04 05 06 07 08 09 10 11 12 ... 98 99 0 1 2 ...

Doing so only makes partial sense if the LED indices for the tens digit are re-assigned to be 1 to 10 instead of 0 to 9. But that doesn't make sense when counting past 99 when the 10s digit becomes 2 digits (10), wrapping from 109 to 0 and continuing from there. The code below is my suggestion of a replacement that keeps the feature of leading-zero blanking and has some other style changes -- Button A and B are similar and simpler, 99 is a high limit similar to 0 being the low limit, and colors I prefer.

let isTen = false
let isDigit = false
let cntGT9 = false
let tens = 0
let digits = 0
let count = 0
function render() {
music.playTone(262 + count * 50, music.beat(BeatFraction.Quarter))
digits = count % 10
tens = (count - digits) / 10
cntGT9 = count > 9
light.clear()
for (let i = 0; i <= 9; i++) {
isDigit = i == digits
isTen = i == tens
if (cntGT9 && (isTen && isDigit)) {
light.setPixelColor(i, 0x0000ff)
} else if (cntGT9 && isTen) {
light.setPixelColor(i, 0x00ff00)
} else if (isDigit) {
light.setPixelColor(i, 0xff0000)
}
}
}
input.buttonB.onEvent(ButtonEvent.Click, function () {
if (count < 99) {
count += 1
}
render()
})
input.buttonA.onEvent(ButtonEvent.Click, function () {
if (count > 0) {
count += -1
}
render()
})
render()