New snippets for Spanish lesson index

[mdlincoln]

While waiting to figure out the JS problems on #623, we can at least translate these snippets.

Closes #623

[mdlincoln]

@vgayolrs can you please push commits here: https://github.com/programminghistorian/jekyll/blob/lesson-filter-es-fix/_data/snippets.yml#L135-L140

Please add your commits to the lesson-filter-es-fix branch

[vgayolrs]

Thanks @mdlincoln . I'm on it. Let me review carefully some details. I'll let you know when I'm done.

[vgayolrs]

ok @mdlincoln , I think it's ready to merge.

[mdlincoln]

Thank you @vgayolrs. We still need to fix the Javascript issue before these snippets can be displayed, unfortunately. I'll keep working on it.

[vgayolrs]

You're welcome @mdlincoln . Let me know if there's anything else I can do. Unfortunately, no javascripts at the moment.

Reviewed before PR was complete

[mdlincoln]

So @walshbr I know no javascript whatsoever but I think I hacked my way through this. As described in the original issue, the problem is that we can't use liquid includes within lessonfilter.js, so we need to find another way to pass the proper text labels through to javascript. I think I've done that here.

One question: do you know how to properly set $('#date-sort-text').attr('label') and $('#difficulty-sort-text').attr('label') into variables so they properly render in that text() function? I feel like this could be DRY-er - right now I call each of those queries twice, which is awkward.

[walshbr]

That what you had in mind @mdlincoln? Check out the last commit where I set the variables at the bottom of the js file. One issue with how I did this, I think, is that it sets the labels on each page load. So if the file gets loaded on a page where those labels don't exist we'd get some unexpected behavior. But it appears that this js file is only getting included on the lessons page anyway, so that problem never arises.

And great job figuring it out! I couldn't quite wrap my head around what you meant in the original note on this issue, so I'm glad that you figured it out.

[mdlincoln]

Ah I see - I'd tried saving them to variables somewhere else in the JS and it wasn't working.

I think this is ready for merging if you agree @walshbr

[walshbr]

Looks good to me! We can open separate tickets if anything arises. But seems like the functionality is working as expected, and I'm not seeing errors in the console anywhere.