fix(python): ensure Raises: section is after Returns: section in google style

[hassec]

Changes google_docstrings.lua template to ensure the Raises: section is after the Returns: section, as is shown in the Google Style Guide

Closes #193

[ColinKennedy]

I don't see anything in Google's styleguide saying that Raises is meant to come beforehand, just a couple examples where it does. Luckily Google does have a way to seek clarification. e.g. in the past I asked + PRed to google/styleguide#505

We've got a custom pylint GoogleDocstringChecker internally that verifies the our style of docstring format. My internal response to this kind of question is generally to defer to whatever our lint checker implementation asks for when it comes to details like this. Running your final example through that, it likes it. Which is a strong indicator that we allow that nice readable form. :)

It'd be good to get confirmation before moving forward with this PR.

[hassec]

@ColinKennedy let's see if someone from Google replies. Otherwise, I'd argue that w/o guidance, following the Google examples would be the more reasonable default, or make it configurable.