Having some interactive elements forces the screen readers to switch to form mode
and consequently they delegate the keyboard stuff to the browser.
This patch sets an aria label on each editor in order to have a better description than just
'application'.
Currently we manually localize and update the DOM-elements of the AltText-button, and it seems nicer to utilize Fluent "properly" for that task.
This can be achieved by introducing an explicit `span`-element on the AltText-button (similar to e.g. the regular toolbar-buttons), and adding a few more l10n-strings, since that allows just setting the `data-l10n-id`-attribute on all the relevant DOM-elements.
Finally, note how we no longer need to localize any strings eagerly when initializing the various editors.
It has been tested with Voice Over (mac) and with NVDA (windows).
When an added stamp annotation is focused, the screen reader will announce
that it's a figure containing a graphic with the added alt-text.
For the Firefox pdf viewer, we want to use AI to guess an alt-text when adding an image to a pdf.
For now the telemtry stuff is not implemented and will come soon.
In order to test it locally:
- set enableAltText, enableFakeMLManager and enableUpdatedAddImage to true.
or in Firefox:
- set browser.ml.enable, pdfjs.enableAltText and pdfjs.enableUpdatedAddImage to true.
