Add optional subtitle field

[bchartoff]

Allow for subtitle for both regular and small multiple charts

[bchartoff]

Should be all set, @vivhou please see cfdf828e66bb7549f6f25f2a667647ab21f5b35f for single graphs and 7d483b4aad38a4cb5bc4669e456aa81e8ae933d8 for small multiple graphs. Examples of implementation are in changed files. To close, please:

• Remove "Test subtitles" from all 3 locations:
  • https://github.com/UI-Research/college-affordability.urban.org/commit/cfdf828e66bb7549f6f25f2a667647ab21f5b35f#diff-120f66341311a290aa8b05194eaec24fR1
  • https://github.com/UI-Research/college-affordability.urban.org/commit/7d483b4aad38a4cb5bc4669e456aa81e8ae933d8#diff-48b043b64820abce81fdf88d88367709R27
  • https://github.com/UI-Research/college-affordability.urban.org/commit/7d483b4aad38a4cb5bc4669e456aa81e8ae933d8#diff-48b043b64820abce81fdf88d88367709R68
• Test with actual subtitle content, make sure everything looks good
• Go ahead and close the ticket if all seems well

[vivhou]

This looks good, except do we want to make it bold or even increase the spacing between the title and subtitle, just so it stands out? Or we can leave as is and see if everyone else is fine with it!

[bchartoff]

Good call, really should have tackled this earlier, but these titles don't align to style guide, since line height is way too big. I think updating line heights and spacing helps, what do you think @vivhou ?

Commit c54e8f7d8cf267efd7bb8192fc2b4284f548b26e

New title/subtitle:

Style guide title/subtitle:

Two images overlayed:

[vivhou]

Yes that definitely looks much better, thanks!