Use [Exposed] consistently

[zcorpan]

I accidentally pushed 30dab2c directly to gh-pages when I meant to create a new remote branch. :-(

The change has no normative impact, but is necessary for whatwg/webidl#365

Filing this here for better visibility and FYI, and in case somebody likes to review the change. cc @annevk @tobie

Will keep this open to track updating interfaces.html in web-platform-tests.

[annevk]

r+ for index.bs changes.

[silviapfeiffer]

Fine by me. No worries about this change.

Since this is something that can happen quite easily accidentally, how about using GitHub's safety features? In the settings for this repo, you could change the gh-pages and master branches to protected branches to require reviews before landing. Just a thought.

[zcorpan]

@silviapfeiffer thanks, I've now ticked some checkboxes in settings.