Add default failbacks

[paltman]

No description provided.

[paltman]

Add fallback messages when no data is returned for a given annotation

[jacobwegner]

@paltman I think you included portions of #30 in this PR (likely to pick up adding the fallback to the widget). I'm about to approve #30 so no harm no foul.

[jacobwegner]

@paltman This is another thing where I feel like our acceptance criteria in Trello is not thorough enough.

Looking at
https://deploy-preview-37--explorehomer-dev.netlify.app/reader?urn=urn%3Acts%3AgreekLit%3Atlg0012.tlg001.msA-folios%3A12r.1.1-12r.1.25, we have better fallbacks on the widgets:

But not on the display mode (e.g. sentence alignments here):

or the metrical annotations:

(We do have a good fall back on the folio images though already)

[jtauber]

The first thing that's clear is that we're completely inconsistent in the styling of the widget fallback.

• different font size
• different indentation
• "No X available" vs "No Y" vs "No Z found"
• period vs no period

My slight preference is the Named Entities variant. I certainly prefer the smaller font size, less indentation, and no period.

Not sure what which I prefer between "available" or "found" or neither.

[paltman]

I'll make a component called <EmptyMessage> that can have it's own single style.

[paltman]

@jtauber everything is now the same font/size/padding/message. It's a default message in a slot so we can override with specific language. Just let me know what language you want in what widget/place.

[jtauber]

For the side widgets, I'd drop the text-align: center; and change the padding to padding: 0 0 0.4rem;

I understand the centering and margins are needed when in the reader widget (metrical annotation and folios) but in side widgets they take up a bit too much space and draw too much attention.

[paltman]

@jtauber fixed