[spell-check] Fixes for a possible patch release

[savetheclocktower]

A couple fixes need to be applied to spell-check; this is the PR that will hold them. Opening as draft for now; I'll commentate as I add commits.

[savetheclocktower]

First we need to fix CI; there's a failing test in the spell-check specs. This test passed for me on macOS, but is failing on Linux, so I can only assume that the Linux dictionary considers foo to be a word, and macOS’s dictionary doesn't. We'll soon see if my theory is correct!

[savetheclocktower]

This commit removes the console.log I left in inadvertently… and also applies some small fixes to eliminate some ESLint gripes with the specs.

[savetheclocktower]

Finally, I'm probably going to argue for reverting the change we made to the default spell-check.grammars setting. Here's why:

• There's something a bit dumb about this package: whenever an edit is made and the editor has stopped changing for a short period of time, the entire document is re-checked. This is rather costly when the document is large (like a several-thousand-line–long source code file). The spell-checking happens in a background thread, but if you're making frequent changes to a certain file, the checking happens often, and it's CPU-intensive. It could be quite a battery drain.
• So at the very least it could be argued that adding source comment was premature, and that it would be better to revert this change and instead add the ability for spell-check to check/recheck the buffer incrementally. This is worth doing even independent of our decision with this setting.
• Still, after having used this feature for a few days, I'm completely on the fence about whether it's desirable for the average user. It has helped me spot a few typos in my code comments, but it also complains about things that aren't words — like camelCasedMethodNames — and those aren't actionable. It also complains about file extensions — so if I make reference to a highlights.scm file in a code comment, the scm has a red squiggle underneath.

For now I'd like to revert the change to spell-check.grammars setting, and then we can have the debate later on when spell-check is a bit more considerate of the user's system resources. If a user still wants it, they can add the value back in the package settings — the part that enables selective buffer checking isn't going anywhere.