Remove/lesson dependency on "Convert line breaks into HTML"

It's also worth noting that the current implementation does not correctly handle line breaks in accordance with the Markdown spec.

Currently line breaks within a paragraph always get converted to a <br> tag. Markdown is intended to allow paragraphs to be formatted with line breaks in the source document, to allow easy readability while composing. To insert a line break, a line should either be ended with 2 or more spaces, or a HTML <br> tag.

I think removing the reliance on the "Convert line breaks" filter would allow CommonMark to handle line breaks correctly according to the Markdown spec, though I haven't yet tested this.

This change didn't require much, other than disabling the requirement for the "Convert line breaks" filter.

Once disabled, all that's needed is to add <p> and <br> to the list of allowed tags.

CommonMark then handles line breaks correctly.

I would like to add some test cases around correct formatting of line breaks, then should be ready for review.

Great - thank you, @lostcarpark!

MR looks great (so far 😀)

I don't recall why I felt the need to encourage the use of the "Convert line breaks into HTML" text filter in the first place. I partially blame @lostcarpark because I'm pretty sure we were sitting together at Dev Days Vienna when I was working on this 😜

-mike

Changing to work against the 2.0.x branch. Hopefully, no refactoring necessary. 🤞🏼

Thank you for working on this so quickly.

The merge request looks good to me. It feels like a triple win: less code, easier to setup, and better Markdown compatibility.

Just a small heads-up that the README.md still needs to be updated to reflect this change. I didn't see that in the MR.

Thanks for the feedback.

I'll make sure I update the README.

I also want to improve test coverage (there's one test that's passing that I think should fail with this change, so I'm wondering if it was actually working as expected).

Rebased against 2.0.x branch, and fixed conflicts.

• I added a test, testParagraphs() that line breaks are handled correctly.
• I updated the checks of Markdown Easy filters in Status report, and updated the test of it using xpath, as the CSS based checks seemed to always be passing, even when they shouldn't.
• I updated the "tips" list on the config form, which was including the list HTML in the translatable string. It's now using an item_list render array, with separate translatable strings.
• Finally, I've updated the README, and hope I've adequately covered the changes.

Some concerns:

• We now have 6 bullets in the "tips" on the filter page. Is that too much, and is there scope for rationalizing?
• The README could do with some careful review to make sure my additions are correct, and that I haven't missed anything.

I reviewed the patch and it looks good.

That said, it might change quite a bit depending on what happens with the "Limit allowed HTML tags" filter. It could be best to wait for that decision?

Before finalizing this issue, let's decide on #3530906

(Very) temporarily postponing this issue.

-mike