If a category title contains a period, then the period and the rest of the title is excluded from the category name in the category overlay.

The category overlay JavaScript file should use title.getMainText() instead of title.getNameText()

QA

1. Visit https://en.m.wikipedia.beta.wmflabs.org/wiki/Dog
2. Add the page to a category that contains a period.
3. Open up the categories: https://en.m.wikipedia.beta.wmflabs.org/wiki/Dog#/categories
4. Verify the full name is shown including text after the period

QA Results