Localization support

Hello. As it stands, the section dedicated to translation contains instructions for supporting a locale that do not reflect the one in effect on the localization platform chosen by this project—Weblate—which also allows for this result. I speak from experience since **I myself added a locale** to the project via the latter.

It is therefore necessary to ask whether:
- the instructions are not only incomplete but also obsolete;
- there is reason to suspect that a locale added via the localization platform is taken into account by this project, which then apply to the translations carried out.

Start with the section dedicated to translation and compare its locale-support instructions with the project's Weblate setup. Then trace how a locale added through Weblate is handled by the project. Done means the instructions and the project's treatment of Weblate-added locales are clearly documented and any uncertainty is resolved.

Written by the indexing model from the issue text.