Add missing language names

Author: tankerkiller125

frontend/locales/en.json

@@ -262,6 +262,8 @@
         "it": "Italian",
         "ja-JP": "Japanese",
         "ko-KR": "Korean",
+        "lb-LU": "Luxembourgish (Luxembourg)",
+        "lt-LT": "Lithuanian (Lithuania)",
         "nb-NO": "Norwegian Bokmål",
         "nl": "Dutch",
         "pl": "Polish",