This patch changes almost all viewer-components[1] to use "data-l10n-id"/"data-l10n-args" for localization, which means that in many cases we no longer need to pass around the `L10n`-instance any more.
One part of the code-base where the `L10n`-instance is still being used "directly" is the AnnotationEditors, however while it might be possible to convert (most of) that code as well that's not attempted in this patch.
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[1] The one exception is the `PDFDocumentProperties` dialog, since the way it's currently implemented makes that less straightforward to fix without a lot of code changes.
- For the generic viewer we use @fluent/dom and @fluent/bundle
- For the builtin pdf viewer in Firefox, we set a localization url
and then we rely on document.l10n which is a DOMLocalization object.
The main stamp button will be used to just enter in a add/edit image mode:
- the user can add a new image in using the new button.
- the user can edit an image in resizing, moving it.
In image mode, when the user clicks outside on the page but not on an editor,
then all the selected editors will be unselected.
This way we don't have a lot of useless divs and we let the css engine handle the
creation/destruction of the :after pseudo-element.
It'll help to slightly improve performance when zooming.
While it can't hurt to localize the main error-messages, also localizing the error *details* has always seemed somewhat unnecessary since those are only intended for debugging/development purposes. However, I can understand why that's done since the GENERIC viewer used to expose this information in the UI; via the `errorWrapper` UI that's removed in PR 15533.
At this point, when any errors are simply logged in the console, it no longer seems necessary to keep localizing the error *details* in the default viewer.
