[editorial] Typo in manifest-src example

[js-choi]

In the Working Draft, there’s a minor grammatical typo in the example for manifest-src:

Fetches for the following code will return a network errors

Would it be appropriate for a non–Working Group member to open a pull request for an un-substantiative edit like this?

[antosart]

Thanks for reporting this!

According to CONTRIBUTING.md you don't need anything special for a non-substantive contribution. That said, I'm not sure how the ipr check on the github PR would behave. So for simplicity I just went ahead and fixed the typo, hope that works for you.