Text Collides on Concepts Web Docs Page

[cailafinn]

Describe the bug
Colliding of text on the web version of the Concepts index page (The qt one in workbench is fine).

To Reproduce

1. Visit: https://docs.mantidproject.org/nightly/concepts/index.html#concepts-contents

Expected behavior
The link should pass onto the next line with a hyphen, as in the qt docs within workbench.

Platform/Version (please complete the following information):

• OS: All