Update promise.each.md (#1317)

I fixed a few grammatical issues and moved the sentence "If the iterator function returns a promise..." to the first paragraph where it seems to belong since it's part of the iterator logic. It's a pretty important thing to keep in mind and it seemed like an afterthought.

docs/docs/api/promise.each.md

@@ -19,10 +19,9 @@ Promise.each(
 
 [api/promise.each](unfinished-article)
 
-Iterate over an array, or a promise of an array, which contains promises (or a mix of promises and values) with the given `iterator` function with the signature `(value, index, length)` where `value` is the resolved value of a respective promise in the input array. **Iteration happens serially**. If any promise in the input array is rejected the returned promise is rejected as well.
-
-Resolves to the original array unmodified, this method is meant to be used for side effects. If the iterator function returns a promise or a thenable, then the result of the promise is awaited, before continuing with next iteration.
+Iterate over an array, or a promise of an array, which contains promises (or a mix of promises and values) with the given `iterator` function with the signature `(value, index, length)` where `value` is the resolved value of a respective promise in the input array. **Iteration happens serially**. If the iterator function returns a promise or a thenable, then the result of the promise is awaited before continuing with next iteration. If any promise in the input array is rejected, then the returned promise is rejected as well.
 
+Resolves to the original array unmodified. This method is meant to be used for side effects. 
 
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