Taxonomy: Fallback to a language-only-localized category display name if there's no language-country localized one not found.

Suppose you translated category names in a taxonomy document to two different locales: en and fr.
But, suppose you have three different content root folders for each locale: en, en_GB and fr to differentiate content folders for General/US (en), UK (en_GB) and French General (fr).

Now, when you want to select taxonomy categories in a document under General/US folder, it is selecting category names in English properly.
However, if you try to select categories in a document under UK folder, it cannot select proper category names because there's no separate en_UK translations in the taxonomy document.

It would be nice and more convenient if the category display name selection logic [1] is be able to fall back to en when no category is found by en_GB, the more specified locale.

[1] https://code.onehippo.org/cms-community/hippo-plugin-taxonomy/blob/master/addon/frontend/src/main/java/org/onehippo/taxonomy/plugin/TaxonomyBrowser.java