Fix small gap before "chore" in Contributing > Commit Messages

[An-anonymous-coder]

This may be as simple as removing the newline before it in the markdown file:

However, that will break some markdown interpreters (including GitHub's). I don't know enough about how the website is configured to interpret code blocks to know if that will fix it or break it.

If that doesn't fix it, a change may need to be made to the markdown interpreter itself to change how it handles code blocks.