Explain what "coverage" and change mean for code coverage

This is an actionable insight from the UX Department: MRs experience async critique research (insight).

What

In the merge request widget for pipelines, it's not clear what the word “coverage” means unless you're familiar with the concept of “code coverage”. Additionally, it's not clear what a positive/negative change in that value is comparing to.

Why

To increase user understanding and usefulness of this information.

How

Explain what "coverage" and change mean for code coverage

Proposal

• Change "coverage" to "Test Coverage"
• Add a tooltip (add to the tooltip when present for multiple coverages) with language "This change will (decrease/increase/create no change in) the overall test coverage if merged."