Replace numStopped with numStoppedTotal in index.html

[xzl2021]

I replaced numStopped with numStoppedTotal in index.html. If not, It will only show 1000 stopped/finished tasks. I think it is a bug to fix, so I did this. Wish to merge please, thank you. Have a lucky day!

[mayswind]

1. The value of "numStoppedTotal" includes the count of tasks which are not kept in aria2 memory compared to the value of "numStopped".
2. The default volumn of download task result kept in aria2 memory is 1000.
3. AriaNg requests at most 1,000 piece of data via aria2 api each time, which can meet the needs in most cases. If AriaNg want to get whole data, AriaNg should implement paging and more complex functions. At the same time, due to the less resource that web app can get, the page would become more slow. So AriaNg made this limition.

I think this modification cannot solve your problem, and this modification is redundant.