Desktop: Fixes #8448: Merge changes from upstream turndown project

[personalizedrefrigerator]

Summary

The upstream turndown project has bug fixes related to code blocks and whitespace. This should fix #8448 and should partially fix #8435.

Notes

Because this pull request may require further testing, it's still a draft.

[personalizedrefrigerator]

I added this function after merging changes to optionally replace \u00A0 characters with  , making non-breaking spaces noticeable within the markdown editor.

[personalizedrefrigerator]

The HTML input file corresponding to this test contains

		<tr>
			<td>&nbsp;</td>
			<td></td>
		</tr>

which was previously ignored.

It is no longer ignored and thus the test output has been updated.

[laurent22]

Thanks, I think that's a good change, as long as our existing test units are still passing.

• Could you also update the README to mention on which version our fork will now be based?
• Are you able to check that we aren't overwriting our custom code? (that was added to support the web clipper)

There's also turndown-plugin-gfm that contains a lot of improvements for the web clipper, but if it needs to be updated we can do so in a separate PR.

[personalizedrefrigerator]

I've done a small amount of testing and WebClipper still works (and produces similar output).

I'm testing with WebClipper from the Chrome store and the development version of Joplin (changing the web clipper port accordingly).

Example

Clipping the main GitHub repository page for Joplin

Old version of turndown:
turndown-test-old--markdown.md
turndown-test-old--rendered.pdf

New version:
turndown-test-old--markdown.md
turndown-test-new--rendered.pdf.pdf
(Edit: Fixed new version PDF possibly rendered from old markdown)

I've updated the turndown README with information about the commit that changes are based on.

[laurent22]

Looks good, thanks @personalizedrefrigerator!