fixed scss for numbered lists and alternating-bg cards

[johnnyporkchops]

Addresses:
add numbers to list--numbered class : https://github.com/18F/fec-cms/issues/1781
add transparent border to .card--alternating-bg : https://github.com/18F/fec-cms/issues/1734

Numbered lists:

Alternating-bg cards before/after

Before:

After:

[jenniferthibault]

Ran this locally and visually the styles look 👍💯

As per usual, I can't speak to the technical implication, so passing that on to @patphongs 💐

[codecov-io]

Codecov Report

Merging #1789 into develop will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop    #1789   +/-   ##
========================================
  Coverage    79.39%   79.39%           
========================================
  Files           45       45           
  Lines         3261     3261           
  Branches       488      488           
========================================
  Hits          2589     2589           
  Misses         672      672

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[johnnyporkchops]

Added the same styles for numbered lists to apply to html-blocks as well as rich-text blocks. That was the missing piece making testing this so confusing!

[dorothyyeager]

Thank you for working on this John! I will leave the code review for those who know better what it should look like, but am glad to have this done!

[johnnyporkchops]

See the even more offensive example of jumping in upadted screenshot above

[patphongs]

Thanks @johnnyporkchops, works well