Adds commenting around banner persistence and makes it so that if you tab to the close button and hit enter, the banner will shut.
Note that if you click or tab+enter on the button accidentally, it may not be clear how to reopen it? That is likely an enhancement to consider another time.
Should be merged prior to https://github.com/18F/foia-hub/pull/725 for ease.
Adds commenting around banner persistence and makes it so that if you tab to the close button and hit enter, the banner will shut.
Note that if you click or tab+enter on the button accidentally, it may not be clear how to reopen it? That is likely an enhancement to consider another time.