Global header navigation items :focus state not visible in Windows High Contrast mode

[joedolson]

In Windows High Contrast mode, the only characteristics of a :focus state that are visible are outline or border, which are both set to empty values on the global header.

Core uses a global outline: 2px solid transparent;, which is invisible in standard modes, but becomes visible in high contrast mode.

See https://meta.trac.wordpress.org/ticket/4111