Fixes menu a11y, and adds landmarks with `F6`-navigation.
Also fixes a GPUI bug, and adds debug actions for dumping a11y tree
info.
Since `F6` was already in use by the pause debugger keybind, also
tightens up the debugger keybind context so they require an active
debugger session. When there is one active, `F6` stays as pause
debugger. `ctrl-F6` always works to go to the next landmark.
Also adds an "accessible mode" setting. Currently, this only controls
whether we show all menus all the time, but I suspect it will expand
significantly in the future.
Also adds `.aria_keyshortcuts()` API, but it's not wired up within
accesskit adapters, so is not yet reported to screen readers.
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Release Notes:
- N/A or Added/Fixed/Improved ...
Cameron Mcloughlin
ab43548338