show bullet points before text?

You can do this with CSS.

Add this to the Additional CSS module of the customizer or with a plugin:
http://www.wpbeginner.com/plugins/how-to-easily-add-custom-css-to-your-wordpress-site/

For bulletpoints use the list-style-type property with value disc

.widget.related_posts_by_taxonomy li {
	list-style-type: disc;
}

For numbered list items use the value decimal.

.widget.related_posts_by_taxonomy li {
	list-style-type: decimal;
}

http://htmldog.com/references/css/properties/list-style-type/