Use contentEditable for our hidden accessibility textArea

[isidorn]

Investigate into using contenteditable instead of a plain textArea for our hidden accessibility field.
It migh have performance implications, but it would allow us to have richer accessibility content on each line. Including line number, breakpoints etc..

[LeonarddeR]

cc @bramd @zersiax

Note that line number support will probably conflict with the ability of the screen reader to provide line numbers itself. NVDA is able to do this. In Visual Studio, this is also an issue.

[zersiax]

While that is true, I would say line numbers can be toggled, so I don't necessarily see that as an obstacle for this. If this allows for breakpoint, error and line number indication, I'd say go for at least giving it a test run. The performance implications are one to keep an eye on, though.

[derekriemer]

NVDA's line number reading is not going to work in vscode, because vscode can only page n lines at a time to the hidden textarea used for accessibility.