Easier `FORMATTER` indenting with context manager?

[davidorme]

We could potentially avoid all the:

FORMATTER.push()
...
FORMATTER.pop()

By defining a context manager:

with FORMATTER.indent_by():
    ...

I think this is clearer, although makes indentation in the code deeper.

[jacobcook1995]

I think the switch makes sense (provided that it doesn't entail too much work). Just in the sense that a context managers are standard python syntax, whereas I lost a bit of time due to not paying enough attention to the exact placement of FORMATTER.push() and pop() statements