Technical details

The space before the dot is a non-breaking space. That means it will not line break and will not collapse together with normal spaces that come before the template.

The space after the dot is a normal space. That means it wraps (allows line breaks) and it will collapse together with normal spaces that come after the template to form one single space.

Under some circumstances dotted link lists misbehave. They might get unexpected line wraps or they might expand outside the box they are enclosed in. The how-to guide w:Wikipedia:Line break handling explains when that happens and how to fix it.