RScript: Display expression blocks( {...}) on a new line

[ghost]

Many statements like if or while statements have a body. In case that the body is an expression block it should be placed on a new line to improve usability. It can be implemented with a indent collection and a condition:

indent-layout-on-new-line:(editorContext, node)->boolean{ 
  node.body.isInstanceOf(BodyExpr); 
}

This would of course need to be implemented in a more generic way.

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