Update Ch18.1 on enumerate

resolves  issue #1994

Author: Zoybean

src/ch18-01-all-the-places-for-patterns.md

@@ -159,7 +159,7 @@ c is at index 2
 
 We use the `enumerate` method to adapt an iterator to produce a value and that
 value’s index in the iterator, placed into a tuple. The first call to
-`enumerate` produces the tuple `(0, 'a')`. When this value is matched to the
+`next` produces the tuple `(0, 'a')`. When this value is matched to the
 pattern `(index, value)`, `index` will be `0` and `value` will be `'a'`,
 printing the first line of the output.