Labelling bot seems unable to identify Windows issues

[sxa]

We should look at the labeller bot and ensure that it can correctly identify issues relating to Windows and tag them with os:windows. I've just added that label to a few issues manually.

Noting that the following is not the same list:

• Search for Windows
• os:windows label

Also noting that the above list includes quite a lot more as some things (such as the new machine template) includes windows in the example list of operating systems so it perhaps needs be looking for windows without / around it. This is probably true of some of the others os/arch labelling too so a general review might be in order.