Use of analyzer in dotnet build/CI

[SmithPlatts]

This is related to #302, but I wanted to add a use-case:

I've worked on a few projects where some devs just do not care about their spelling, and will submit PRs with spelling errors. Sometimes they are simple mistakes, often it is just laziness.

Having the analyzer run as part of any build process would allow us to capture these as part of the code review process in a far more streamlined and deterministic manner.

[EWSoftware]

I can see it would be of use for code reviews but certainly not enabled full time for general development as it would get in the way of other more important build warnings and errors and cause frustration. Adding support for API spell checking was the most requested feature so it was very disappointing to receive a surprising amount of abusive hate mail sent directly to my personal e-mail berating me for adding it because the senders didn't want it even though they could just disable it in the options. That's mostly why I haven't done much with it since then and you can see why I'm reluctant to put it somewhere that is certainly not as useful as in the editor.

It would also need updating to spell check comments and strings which are currently only handled by the editor tagger. In its current state, you'd only catch spelling errors in those by running the spellcheck solution/project option manually within Visual Studio.