add extra newline to output of pretty-simple cli

[cdepillabout]

The pretty-simple CLI program should have an extra newline added to its output.

For instance, currently, the pretty-simple CLI works like the following example:

$ pretty-simple
[1,2,3]<ENTER>
<CTRL-D>[ 1
, 2
, 3
]$

I've also labeled the exact key presses I use. You can see after I input the string [1,2,3], I press Enter and then Ctrl-D. pretty-simple correctly pretty-prints [1,2,3], but there is no newline after the closing ], and the $ from my prompt comes immediately after the ].

There should be a newline between ] and $.