This change does two main things:
1. Indicate that `(for_expression)`'s introduce a `@scope` (this
is the scope for the enumerators to be used within the loop).
2. Indicate that the `(identifiers)` within the `(enumerators)` are
`@definition.var`s.
---
For the following example snippet:
```scala
val fruits = List("apple", "banana", "avocado", "papaya")
val countsToFruits = fruits.groupBy(fruit => fruit.count(_ == 'a'))
for ((count, fruits) <- countsToFruits) {
println(s"with (fruits) 'a' × $count = $fruits")
}
```
The `count` and `fruits` identifiers are new definitions introduced by
the `for` expressions scope.
`@scope` included `function_declaration` while is should have included `function_definition` instead. The former one is used to declare abstract functions while the latter one is used to define functions together with their bodies.
