Update resources/type-system/inference.md

Co-authored-by: Erik Ernst <eernst@google.com>

resources/type-system/inference.md

@@ -343,8 +343,8 @@ schema.
   - If the enclosing function is marked `sync*`, then for each `yield* e;`
     statement in the block, let `S` be the inferred type of `e`, using the
     local type inference algorithm described below with a typing context of
-    `Iterable<K>`. If there exists a type `E` such that `Iterable<E>` is a
-    super-interface of `S`, update `T` to be `UP(E, T)`. Otherwise update
+    `Iterable<K>`. If `S` implements `Iterable<E>` for some `E` then update `T` to be `UP(E, T)`. 
+    Otherwise update
     `T` to be `UP(S, T)`.
     _It is a compile-time error if *S* is not a assignable to
     `Iterable<Object?>`, so either *S* implements `Iterable`, or it is one of