[whatwg/fetch] Sentence fragment when making CORS preflight request (#328)

```
Set request's response tainting to "cors" and request's redirect mode to "error".

The result of performing an HTTP fetch using request with the CORS flag and CORS-preflight flag set. If the result is a network error, clear cache entries using request. 
```
See second sentence.

---
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/whatwg/fetch/issues/328