Update article.md

1-js/12-generators-iterators/1-generators/article.md

@@ -458,7 +458,7 @@ If we don't catch the error there, then, as usual, it falls through to the outer
 
 ## Summary
 
-- Generators are created by generator functions `function*(…) {…}`.
+- Generators are created by generator functions `function* f(…) {…}`.
 - Inside generators (only) there exists a `yield` operator.
 - The outer code and the generator may exchange results via `next/yield` calls.