Fix a small typo in Coroutines proposal

[philipphofmann]

The changed sentence doesn't make sense. I think removing the coroutine fixes it.

[elizarov]

I'm curious of why you think it does not make sense. It was supposed to be an emphasis on the fact the running coroutine is suspended by the suspending function. Maybe it could be further clarified like this:

When a suspending function does not suspend the current coroutine but continues the coroutine's execution, ...

[philipphofmann]

Thanks for your quick reply. So for me, the missing article the was a bit confusing. I'm going to change it to your suggestion. Thanks, @elizarov.

[elizarov]

Thanks!