Put a slash before the dot, like 5\.:

5. Go straight to jail.

This is a Markdown issue really. Starting a line with a number and then a dot turns that line into an item in an ordered list. The most common behaviour (that I’ve seen) is to start that list from 1, regardless of what number is used. The intent is to make it easy to add items later without renumbering everything, for living documents at least.