Update Elementa style with numerous improvements

[akokai]

Fixed several details for a more complete match to the journal style guide.

• Journal titles and issue numbers (important!)
• Collection/series titles and numbers
• Missing dates
• Book Title Case
• other minor things

[csl-bot]

Awesome! You've created a pull request to the Citation Styles Language styles repository. We'll get in touch soon (usually within a day or two). In the meantime, our automated test system will go ahead and run some checks on your pull request. In a few minutes you'll be notified of the test results.

If you haven't done so yet, please make sure your style validates and follows all our other Style Requirements.

To update the current pull request, visit the "Files changed" tab above, and click on the pencil icon (see below) in the top-right corner of your style to start editing.

If you need assistance at any point, please leave a comment and we'll get back to you (feel free to write in Dutch, English, French, German, Portuguese, or Spanish).

[csl-bot]

😃 Your submission passed all our automated tests.

[rmzelle]

Thanks!