Better content assist for methods with closure arguments

Currently, applying a content assist proposal for a method that has a closure argument will do something like this:

myMethodCall null

And the user will have to enter '{', press enter, and then the closure will automatically be terminated with the closing } placed at the correct location.

We could do better here and do something like this (where '|' is the resulting cursor location):

myMethodCall {
    |
}

The difficulty will be twofold:

1. ensuring that the resulting cursor is placed one indent-level past the indentation of the method call
2. ensuring that the closing '{' is also placed at the correct indent level.

Not impossible, but there is currently no mechanism to check this inside of our content assist infrastructure.