Sanitizing markdown text.

[jbicker]

What it does

#7954: It sanitizes the html which is shown in markdown preview.

How to test

1. Create markdown file
2. append the following text: <style onload="alert(0)"> and/or <script>"alert(0)"</script>
3. Save and close the file.
4. Right click the file and select Open With -> Preview
5. Observe the alert is not fired.

Review checklist

• as an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• as a reviewer, I agree to behave in accordance with the review guidelines

[vince-fugnitto]

@jbicker it looks like some of the markdown tests need to be updated following the changes (CI is red).

[jbicker]

@jbicker it looks like some of the markdown tests need to be updated following the changes (CI is red).

Thanks. looking into it.

[vince-fugnitto]

The changes look good to me!

I verified that:

• the new dependency is license approved using our clearly defined process
• the markdown script is not executed (it is on master)