Pylint warning for extract.py

pylint is complaining that an "Anomalous backslash in string: '\-'"
The string constant might be missing an 'r' prefix.

editor/translations/extract.py

@@ -116,7 +116,7 @@ shutil.move("editor.pot", "editor/translations/editor.pot")
 
 # TODO: Make that in a portable way, if we care; if not, kudos to Unix users
 if (os.name == "posix"):
-    added = subprocess.check_output("git diff editor/translations/editor.pot | grep \+msgid | wc -l", shell=True)
-    removed = subprocess.check_output("git diff editor/translations/editor.pot | grep \\\-msgid | wc -l", shell=True)
+    added = subprocess.check_output(r"git diff editor/translations/editor.pot | grep \+msgid | wc -l", shell=True)
+    removed = subprocess.check_output(r"git diff editor/translations/editor.pot | grep \\\-msgid | wc -l", shell=True)
     print("\n# Template changes compared to the staged status:")
     print("#   Additions: %s msgids.\n#   Deletions: %s msgids." % (int(added), int(removed)))