add placeholder for about style

[jkup]

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed)

Fix #5195

Auditors @bbondy @bsclifton

Test Plan:

Go to about:style and make sure you see something (just the word typography and four headers for now!)

Should it just be blank for now? I can start adding all of our components ASAP.

[bbondy]

++ great stuff

[luixxiul]

Note: It has been renamed to about:styles with #5320, as referenced above.