added 'nb' to list of country codes (had only 'nn')

Author: NSoiffer

addon/globalPlugins/MathCAT/MathCATPreferences.py

@@ -225,6 +225,7 @@ def languagesDict() -> dict[str, str]:
 			"mt": "bil-Malti",
 			"my": "Myanmasa",
 			"na": "Dorerin Naoero",
+			"nb": "Norsk (nynorsk)",
 			"ne": "नेपाली",
 			"ng": "Oshiwambo",
 			"nl": "Nederlands",