Fix VO nav in Firefox

[cajunluke]

On Mac!Safari, using Voiceover to follow toc links bounces to the proper heading in main. This does not happen in Firefox; following the link there scolls the page as normal, but the user has to navigate manually to headings.

[cajunluke]

Note: some vo users can use headings to navigate; can we tell vo to skip the toc?

[dispatchrabbi]

I think we can? But we ought to check with a VO agent before doing so.

[cajunluke]

I talked to a friend who uses VO, and they think it might be a Firefox bug, the way it works in Safari is correct. I’ll have a look to see if there’s a Firefox bug on it