Comment by jeroenhd

<p> indicates a new paragraph. <li> indicates a new list item. Unless otherwise specified, the existing paragraph/list item continues. There's nothing magic about any of this, it's part of the HTML spec.

Laziness doesn't play a role. This isn't XML where you need to repeat yourself over and over again or abusing a bug in the rendering logic; it's following the definitions markdown language you're writing content in.

If you're not too familiar with the HTML language then it's always a safe bet to close your tags, of course.