feat(options/language): improve description & add translations

src/public/app/widgets/type_widgets/options/i18n/language.ts

@@ -1,10 +1,12 @@
 import OptionsWidget from "../options_widget.js";
 import type { OptionMap } from "../../../../../../services/options_interface.js";
 import { getAvailableLocales } from "../../../../services/i18n.js";
+import { t } from "i18next";
 
 const TPL = `
 <div class="options-section">
-    <h4>Languages</h4>
+    <h4>${t("content_language.title")}</h4>
+    <p>${t("content_language.description")}</p>
 
     <ul class="options-languages">
     </ul>

src/public/translations/en/translation.json

@@ -1690,5 +1690,9 @@
   "note_language": {
     "not_set": "Not set",
     "configure-languages": "Configure languages..."
+  },
+  "content_language": {
+    "title": "Content languages",
+    "description": "Select one or more languages that should appear in the language selection in the Basic Properties section of a read-only or editable text note. This will allow features such as spell-checking or right-to-left support."
   }
 }