[PM] Cleanup WebPlatformDocs css.json

[jasonsanjose]

Comment from pull #3449

• use lowercase instead of uppercase properties
• remove unnecessary forward slash escaping
• resize the inline widget when the sidebar visibility changes

[jasonsanjose]

@peterflynn has already addressed the widget resize problem.

[jasonsanjose]

Reassigned to @adrocknaphobia

[redmunds]

Moved to Sprint 25.

[njx]

Looks like this didn't get done. Moving out to sprint 26.

[gruehle]

Moving out to sprint 27.

[redmunds]

@adrocknaphobia Don't forget to update the WebPlatformDocs css json files before it gets too late in the sprint :)

[njx]

Moved to sprint 29

[pthiess]

@adrocknaphobia Moving to Sprint 30

[njx]

Removing from sprint. This isn't high priority. We'll use #4763 as a placeholder for the issue that it's becoming urgent to figure out how we're going to deal with these bugs.

[redmunds]

Was assigned to adrock, so marking "Needs Review".