Report candidates on closing list terminators

From @robpalme: https://twitter.com/robpalmer2/status/1190383568612184064 ```ts function base_init() { { } function me() { } ``` https://www.typescriptlang.org/play/?ssl=8&ssc=1&pln=9&pc=1#code/GYVwdgxgLglg9mABAIwIYGcCmB9GYZQAUAlIgN4BQliNiFAvhRbYqJLAogLaYnnO0GFIA # Motivation When an ending curly brace (or similar) is missing, we can give some better hints to the user. In some cases, this might be because a stray `}` throws parsing off. # Suggestion It would be very cool to explain a possible reason that the user is getting a `'}' expected` error: > ``` > } > ~ > This '}' occurs at the same indentation level, but corresponds to a different brace. > ```