feat: Warn when named codeblocks lack classes
Description
This adds a warning for when code blocks have IDs but are not one of .file
or .example
.
Closes: #322 (closed)
Checklist
-
You have read, and followed the guidance in, the CONTRIBUTING guide -
The MR content has run through a pipeline, or at least has pipelines enabled. -
There are no licence concerns with this contribution (The README clearly states Subplot is MIT-0)