Disabling unicode isolation on per-placeable basis

[Loskir]

Is there a way to disable unicode isolation for certain placeables? For example, where I am sure that I'm using <bdi> correctly. But without disabling it everywhere else

[zbraniecki]

I don't think there is, but I can see a value of such addition. We currently allow to disable it per formatter - so you could create Localization for FluentBundle, disable it for this one, and use it only for this one message.

But if you have ideas for PRs to improve that, I believe @eemeli would consider it!

[eemeli]

I'm not sure that an option or some other toggle for this would necessarily make sense; we should instead endeavour to make this work automagically.

At the moment, we add the marks unconditionally if useIsolating is set:

fluent.js/fluent-bundle/src/resolver.ts

Lines 344 to 352 in 8c2eae4

	if (useIsolating) {
	result.push(FSI);
	}
	result.push(resolveExpression(scope, elem).toString(scope));
	if (useIsolating) {
	result.push(PDI);
	}

Would it make sense or be sufficient to detect if the stringified value already starts & ends with FSI/PDI before adding those, or would the appropriate conditional here be more complicated?