support sort rules by error count

[tjx666]

Expect

I want the rule with max error count at the top.

Why

1. I want to fix the rule with many errors one by one. And then fix the all rule with few errors one time.
2. By sort the rules with error count, I can see which rule annoy user most

[IanVS]

That's not a bad idea. Right now they are sorted by rule name, but maybe it makes more sense to sort by errors. Though, would you want the most errors or the least at the top? I could see reasons to want either one (knock out the easy ones first, or dig into the biggest problems first).