Update ie.ngdoc

**Browser**: IE8
**Component**: docs
**Regression**: no

Text specifies "polyfill JSON.stringify for IE7 and below" conditional comment for loading the polyfill was "lte IE 8". According to https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify IE8 supports JSON.stringify, so the text was correct, conditional comment was wrong.