The bulk of this updates transcripts to put spaces around the language
name in code blocks. E.g.,
```` markdown
```ucm:hide
````
becomes
```` markdown
``` ucm :hide
````
This corresponds to
https://share.unison-lang.org/@unison/website/contributions/11, which
updates the docs in the same way.
This is effectively a fix for #5214, but that issue also has good recommendations for future changes to info strings, so
I don’t know that it should be closed.
`cmark`’s pretty-printer matches our output pretty well, with a few differences:
- it puts a space between the fence and the info string for in code blocks;
- it prefers `-` over `*` for bulleted lists (as do I) and it indents them;
- it `\`-escapes certain chars very conservatively;
- it prefers indented/unfenced code blocks if there is no info string; and
- it prefers `*` over `_` (unlike any sane person).
This also shows how the change fixes a number of issues:
- fix2158-1.output.md also illustrates how this change fixes#1809;
- alias-many.output.md and input-parse-errors.output.md show how fenced
code blocks without an info string would use the beginning of the
content as the info string;
- transcripts-round-trip/main.output.md shows how output blocks for
generated `unison` stanzas (which could contain nested fenced blocks)
might not have long-enough fences; and
- error-messages.output.md and generic-parse-errors.output.md show how
Unison errors were reported on the wrong line number (and thus the
printed error lines were also incorrect).
