Now we only tokenize the file once, and we pass
**validated** tokens to the pretty printer.
There are a few reasons for this:
* It obviously saves a lot of extra computation
just in terms of tokenization.
* It allows our validator to add fields
to the Token objects that help the pretty
printer.
I also removed/tweaked a lot of legacy tests for
pretty_print.py that were exercising bizarrely
formatted HTML that we now simply ban during the
validation phase.
This directory contains scripts that are used in building, managing,
testing, and other forms of work in a Zulip development environment.
Note that tools that are also useful in production belong in
scripts/ or should be Django management commands.