Addon request. Leech counter.

I suppose it must be easy to code. The idea is straightforward: by default, Anki tags a card as a leech when it fails reviews several times in a row. But if it's already tagged as a leech Anki does nothing. The addon changes this behaviour. For the first time, it uses tag "leech(1)" instead of "leech", for the second time that Anki declares the card as a leech the addon replaces "leech(1)" with "leech(2)" and so on.

Also if a card is already a leech when we start reviewing it, then during its review there will be shown an indicator that displays a number of times when Anki declared it as a leech (this number is based on its tag). For example, if previously this card was declared as a leech two times, then it will display "2"