Mention draw call in TranslationServer.set_locale

**Your Godot version:** 4.3 stable

**Issue description:**
I wondered how to change text on buttons and labels when the user selects a new language, and only recently noticed that TranslationServer.set_locale would trigger draw calls to all or some Control nodes, meaning %label.text = tr("...") in _draw is sufficient. I suggest that this behavior (or a link to the full explanation) should be mentioned in the method description of set_locale. While this detail may be pretty trivial, I believe that there is still a (possibly large) gap between those who (1) use set_locale method (like myself) and who (2a) imagine this behavior independently or (2b) find it being documented already somewhere else.

**URL to the documentation page (if already existing):**
https://docs.godotengine.org/en/stable/classes/class_translationserver.html#class-translationserver-method-set-locale