REPL editor hint to open the accessibility help dialog

[amunger]

have an aria label with an AccessibilityVerbositySetting to point to an accessibility help view

[amunger]

verification steps:

• get the latest pre-release for python extension
• run Python: Start native Python REPL
• execute some expressions from the input box
• with a screen reader enabled, focus on the input box and history list view and ensure there is a hint to open the a11y help for both (the aria label for the input box is a bit overloaded right now)