Help Center links keep your place after you sign in, and other fixes

Fixes

• Signing out through a link that sends the browser to the sign-out page now lands on the login page, instead of showing a page of raw data.
• Signing in from a Help Center link now keeps the exact page you were sent to, including its query string, rather than dropping you at the wrong Help Center page.

Improvements

• Screen counts on Home and the Screens page no longer animate. They’re easier to read at a glance, and easier on anyone sensitive to motion on screen.