Fix a spacing bug in the expandable content

[jimmynotjim]

The expandable content has been missing it's bottom spacing for some time. Half the problem is that we started removing bottom margin from the p:last-child a while back. This fixes that particular issue by adding bottom margin to the :after pseudo element. Margin bottom is used over padding because it naturally collapses when the height is set to 0.

Fixes #462

Changes

• Added spacing to the bottom of expandable content

Testing

• While this fixes the css side of things, there's also a bug in the expandable js code that is being addressed at Add onReady utility AtomicComponent#4. If you want to test this you'll need to symlink the atomic component into your cf-expandables directory. Follow these steps

• cd to this repo, checkout this branch, and make the link connections

  cd ~./[Your Repos Directory]/capital-framework/
  git checkout bugfix/expandable-spacing
  npm run cf-link // this makes each component available to other projects and installs the latest from Atomic Component
  

• In another tab cd to the CF sandbox

  cd ~./[Your Repos Directory]/capital-framework-sandbox
  npm run cf-link // this connects each of the local CF components to this repo
  npm run build // build the stuff
  npm start // start the server
  

• navigate to http://localhost:3000/components/cf-expandables/

Review

• @sebworks
• @Scotchester
• @contolini

Screenshots

Notes

• Sorry testing is such a bear, if you'd rather, feel free to wait till the AtomicComponent has been fixed to review this PR. The corresponding AtomicComponent release has been published. Testing instructions have been updated.

Checklist

• Changes are limited to a single goal (no scope creep)
• Code can be automatically merged (no conflicts)
• Code follows the standards laid out in the front end playbook
• Passes all existing automated tests
• New functions include new tests
• New functions are documented (with a description, list of inputs, and expected output)
• Placeholder code is flagged
• Visually tested in supported browsers and devices
• Project documentation has been updated (including the "Unreleased" section of the CHANGELOG)