Login and Registration: Set a more appropriate page title for the "check your...

Login and Registration: Set a more appropriate page title for the "check your email" step of new user registration or password reset.

Follow-up to [48304].

See #40605, #41514.
Built from https://develop.svn.wordpress.org/trunk@48305


git-svn-id: https://core.svn.wordpress.org/trunk@48074 1a063a9b-81f0-0310-95a4-ce76da25c4cd