External links - Githubissues

Add support for external links to the NCIDS.

usa-link--external

Tasks

[ ] Remove external link css from the button package. This is a link package, not button.
[ ] Storybook
- Missing tests for current and new tab, can we would test for spanish in storybook/backstop
- How is this applied to external links in usa-prose?
[ ] Patch translation to [lang=es/en]
- Need Spanish translations for:
  - "External, opens in a new tab."
  - "External."
[ ] Guidance? No link documentation. Is guidance we do have for NCIDS or Cgov?
[ ] Close old PRs in favor of using USWDS's method