encode less-than signs in text context after whitespace

[pjjw]

Initial checklist

• I read the support docs
• I read the contributing guide
• I agree to follow the code of conduct
• I searched issues and discussions and couldn’t find anything or linked relevant results below
• I made sure the docs are up to date
• I included tests (or that’s not needed)

Description of changes

I found a case using remark-cli/remark-lint/remark-stringify where a bare < was getting emitted as markdown when inside of a list and causing rendering problems. This adds a test case to this and adds a definition in unsafe.js to prevent this from happening.

I'm not sure this is the minimal set of unsafe conditions- it does seem to catch my case and not some other cases where a new escape would be annoying, but I haven't really been exhaustive in searching, relying mostly on the existing test suite.

[wooorm]

Hi!
See the rule above: it can’t be html because the 1 cannot start a tag.
Can you maybe provide more info? Some of your wording is vague. What is “cause render problems”