Actually, the HTML code shows an <ol> for that list. It's not related to markdown (which in this case rendered the appropriate HTML code). The numbers (or bullets) being displayed in the left margin is just a browser's default styling. It increases vertical readibility, considering that lists items are meant to be read in sequence.

You can change it via CSS. Just add to your <ol> or <ul> the following: list-style-position: inside. The numbers/bullets consequently become part of the text.

My preference for styling lists is to leave the numbers/bullets outside but apply a margin-left to the lists so that its numbers/bullets fit inside the main wrap.