message: docs badge now links to docs index
diff: # Terminus UI Library
  -[![MIT License][license_image]][license_url] ![documentation coverage][compodoc_badge] [![NPM version][npm_version_image]][npm_url] [![CircleCI][circle_badge]][circle_link]
  +[![MIT License][license_image]][license_url] [![documentation coverage][compodoc_badge]][docs_index] [![NPM version][npm_version_image]][npm_url] [![CircleCI][circle_badge]][circle_link]
  <!--
  -[![Coverage Status][coverage_image]][coverage_url]
  -->
  [compodoc_badge]: docs/images/coverage-badge.svg
  +[docs_index]: docs/coverage.html
  [license_image]: http://img.shields.io/badge/license-MIT-blue.svg
  [license_url]: LICENSE
  [npm_url]: https://npmjs.org/package/@terminus/ui
  