Better rendering of expressions

[westonpace]

Currently, if I put in the query SELECT add(l_linenumber, 2) FROM lineitem then the expression is serialized (if you click on the project node you will see this in the list of properties) as:

expressions[0] | (l_orderkey,2)

The column is wrong (l_orderkey instead of l_linenumber) and the function is missing. Ideally, it would be nicer to have:

expressions[0] | add(l_linenumber,2)