At least when doing a local review, asking it to be thorough results
in a lot more comments on coding style violation so let's add such an
instruction to the global instructions.
This was generated using copilot itself with Claude Sonnet 4.5 as
the backing model.
The idea is to test this out on some PRs to see whether copilot can
provide useful PR reviews. The idea is that it'll be able to take care
of the low hanging fruit like coding style issues and such. Once we get
some feedback on how it performs, we can make more changes to this document
to get it to behave better (assuming we decide to keep using it at all).