Theme Install screen displays encoded entities

[johnbillion]

The theme description (that's displayed in the left hand panel when you view a theme's details) on the theme install screen is output in the template using {{ double curly braces }} which encodes the output instead of outputting it as HTML.

The result is that ampersands show up as & instead of &. You can see this in action if you view details of "Alexandria" in the "Featured" tab.

Is it safe to use {{{ triple braces }}} instead? It should be, but could do with a second opinion as I'm not sure how much sanitising is done in the theme repo.

[nacin]

Hmm. Anything coming back from WordPress.org should be considered safe, but I do not really want to treat it as safe.

[nacin]

In 27962:

Theme Installer: Don't encode description entities/HTML.

props johnbillion.
fixes #27641.