Add test coverage visualization to global navigation
I noticed: https://docs.gitlab.com/ee/user/project/merge_requests/test_coverage_visualization.html lacked a global navigation entry.
This MR adds it: http://eread-add-test-coverage-visualization-to-nav.178.62.207.141.nip.io/ee/user/project/merge_requests/test_coverage_visualization.html
Edited by Evan Read