Previously, a code block was anything between triple-backtics, including inline
blocks:
some text ```
not a codeblock, but highlighted as one
``` other text
and even if the closing backticks had the wrong indent:
```
this is a code block containing a triple backtick
```
this is still a code block, but Kakoune thinks otherwise
```
Now we use the -match-capture flag to ensure the start and end fences have
exactly the same indent.
Previously, the generic code-block region was defined first, which meant that
it took priority over all the language-specific highlighters. Now we define
the generic code-block highlighting *after* the others, which fixes#2304.
Previously, code-spans were defined as ordinary inline markup, but in Markdown
ordinary formatting doesn't work inside code-spans. Therefore, they are now
regions unto themselves, defined according to section 6.3 of the CommonMark
spec <https://spec.commonmark.org/0.28/#code-spans>, which addresses a comment
on #2111.
535abe2ba7