CI: fix markdownlint script

Since the while loop ran in a subshell, changes to the MDL_FAILED variable aren't visible to the parent, so the job always succeeded. Woops

Fix it and reflow markdown to pass. I highly recommend using an IDE plugin for markdownlint while working on markdown files as it can show inline warnings (in vscode if you turn them on!). A markdown formatter is also good ("format document" in vscode).

resolved all threads

approved this merge request

added 2 commits

• f028a88f - CI: fix markdownlint script
• 14c8243f - treewide: actually pass markdownlint

Compare with previous version

merged

Thanks for being on top of these details!