Unclosed tags is a common lint error, often with visible effects. It should be detected as a lint error.

Steps to replicate the issue

• Replace editbox contents with Some text here <pre> Some text here.

There's no lint error for <pre> being unclosed.

• Replace editbox contents with Some text here <pre> Some text here <pre>

There's no lint error for the closing tag being <pre> instead of </pre>.