fix: Python 3 issue on re (#13230)

Python 3 interprets string literals as Unicode strings, and therefore \s and \g are treated as escaped Unicode characters.

Fix: Declare RegEx pattern as a raw string instead by prepending r

frappe/translate.py

@@ -650,7 +650,7 @@ def write_csv_file(path, app_messages, lang_dict):
 
 			t = lang_dict.get(message, '')
 			# strip whitespaces
-			translated_string = re.sub('{\s?([0-9]+)\s?}', "{\g<1>}", t)
+			translated_string = re.sub(r'{\s?([0-9]+)\s?}', r"{\g<1>}", t)
 			if translated_string:
 				w.writerow([message, translated_string, context])