[Clients] Gemini and accessibility regarding preformatted code blocks

[Sean Conner]

It was thus said that the Great Bradley D. Thornton once stated:
> On 2/25/2021 11:42 AM, Devin Prater wrote:
> 
> > But then we get to preformatted blocks, and the dreaded Ascii graphics.
> > This is what I?ve always disliked about all plain text mediums. MUD?s
> > use Ascii maps and compass and all that. Gopher uses Ascii graphics. And
> > now Gemini too. Sure, it?s wrapped up in a pretty block, but as I?ll
> > discuss in a moment, that isn?t necessarily helpful.
> 
> The Author of Ariane, an Android Gemini app available from F-Droid, was
> himself lamenting ASCII art images in Gemini recently from his Fediverse
> account.
> 
> I solicited a response from him but to date have heard absolutely
> nothing from him. But here's what I did in the meantime.
> 
> ```ASCII-art blah blah blah
> 
> content
> content
> content
> ```

  I might suggest something like:

	preformat = "```" [ [WSP] tag ] [ [WSP] alt-text] end-of-line
	tag       = '@art' / '@code' / '@data' / '@poem'

  Some examples:

``` @code
x = 5
```

``` @art Obligatory Cat picture
cat
```

``` @data Price list
widget	3.45
gadget	5.99
fob	1.99
```

``` @poem
There once was a person from Nantucket ...
```

``` Just some regular alt-text
blah
```

```
nothing special here
```

  The '@tag' format marks out the tag, which I expressly limited to just
four categories for simplicity---one to mark ASCII (or maybe UTF-8?) art,
one for code samples, one for tabular data and one for poetry.  It's not
mandatory, but it could help a client decide how to handle the block.

  -spc