[After soft launch] Change "OPTIONAL" (etc) capitalization

[gohai]

(Apologies, I've been modifying this on pages that I reviewed without realizing that there was a style guide...)

To my eyes, the capital OPTIONAL looks quite out of place, the website isn't using capitalization elsewhere (not even in the headings). How would people feel if we made this a button/pill-like "badge" instead? e.g. like this (which is too big, but I hope it conveys the idea)

[MOQN]

Thank you @gohai! The style guide is outdated! Let's work on is after the launch!