Summary: See downstream <https://phabricator.wikimedia.org/T902>. Currently, timezones are rendered with their raw internal names (like `America/Los_Angeles`) which include underscores. Replacing underscores with spaces is a more human-readable (and perhaps meaningfully better for things like screen readers, although this is pure speculation). There's some vague argument against this, like "administrators may need to set a raw internal value in `phabricator.timezone` and this could mislead them", but we already give a pretty good error message if you do this and could improve hinting if necessary. Test Plan: Viewed timezone list in {nav Settings} and the timezone "reconcile" dialog, saw a more-readable "Los Angeles". Reviewers: amckinley Reviewed By: amckinley Differential Revision: https://secure.phabricator.com/D20559