Consider a notebook with a cell with two lines of code:
[1, 2, 3]
"foo bar"
The default in notebooks is to just render/show the value of the last expression (`"foo bar"`). In pdit, the value of all top-level expressions are rendered/shown:
[1, 2, 3] #=> [1, 2, 3]
"foo bar" #=> "foo bar"
In that way it is more like a REPL than a notebook, you could say.
What does this mean though: "By default, pdit shows output from each top level expression" ?