remove AccessibleBuffer (#4427)

* remove AccessibleBuffer

* rm more

* Update src/browser/Terminal.ts

* rm css

src/browser/LocalizableStrings.ts

@@ -10,6 +10,3 @@ export let promptLabel = 'Terminal input';
 
 // eslint-disable-next-line prefer-const
 export let tooMuchOutput = 'Too much output to announce, navigate to rows manually to read';
-
-// eslint-disable-next-line prefer-const
-export let accessibleBuffer = 'Accessibility buffer';