[Feature Epic] Tuples

[JorgeCastilloPrz]

This covers the complete Tuples feature.

Requirements

• [x] Fold tuples from e.g: Tuple2<A, B> to (A, B) for readability. Only for the parent tuple, we don’t want to fold nested tuples.
• [x] Listen to caret and collapse all folding regions in the document except for the current line one. That gets expanded on click.
• [x] Click folded tuple to unfold it. E.g: (A, B) -> Tuple2<A, B>.
• [x] ~Line marker with icon and explanation that clarifies what is happening when folded.~
• [x] Add ellipsis / truncate in the end when there are more than 5 elements in the tuple. (#702 )
• [x] Tests for the feature
• [ ] Documentation