i18n: return 'key' if 'key' is not in locales files

src/invidious/helpers/i18n.cr

@@ -65,9 +65,11 @@ def load_all_locales
 end
 
 def translate(locale : String?, key : String, text : String | Nil = nil) : String
-  # Log a warning if "key" doesn't exist in en-US locale
+  # Log a warning if "key" doesn't exist in en-US locale and return
+  # that key as the text, so this is more or less transparent to the user.
   if !LOCALES["en-US"].has_key?(key)
     LOGGER.warn("i18n: Missing translation key \"#{key}\"")
+    return key
   end
 
   # Default to english, whenever the locale doesn't exist,