Lint short description text

[ddbeck]

This adds some JS to check short descriptions against our writing guidelines https://github.com/mdn/short-descriptions/blob/master/writing-short-descriptions.md#writing-short-descriptions.

A few notes to help you review this:

• This supersedes https://github.com/mdn/data/pull/297. There were several changes since the previous pull request. If you looked at the previous PR, it might help to step through the commits on this PR, rather than reviewing the thing from scratch.
• I'm pretty new to JavaScript and Node.js. I'd welcome any comments on style, idiom, etc.
• Once we get actual short descriptions into the data itself, we'll probably want to switch to checking the short description text in the repo, instead of fetching the MDN page (and use a different script to fetch the pages and update the text in the repo). I think this is a first iteration, not necessarily the final say on how to check these things.

Let me know if you've got any questions. Thanks, @wbamberg!

[ddbeck]

[insert discussion on wiki-fixable/source-fixable stuff] Does that make sense?

Yes, it does! I think maybe the right thing here is to leave checks here and remove them when we have an import script that deals with that particular issue.

I'd say in general, use the AirBnb style guide.

I've fixed the semicolons. I tried eslint with the Airbnb style and there are a few issues. Rather than overloading this review, I'll start a separate PR (after this one) to add a linter and clean up the issues it raises.

I'm hand-waving here, but perhaps you could consider having a standard form of "test function"

I sorta started this here. There's now a common function signature for the checks, but it's a little awkward to put the list of checks at the top of the file—JavaScript doesn't like references to undefined functions defined with const. Anyway, there's now a more concise list of checks just before they're invoked, so I think it helps a little. Let me know if you have any more ideas about this.

[ddbeck]

Hi @wbamberg, if you could take a look at this some time this week, I think we can wrap it up before the end of the sprint