Fix flake8 issue

pythonx/jedi_vim.py

@@ -631,7 +631,7 @@ def rename():
         vim_command("let s:jedi_replace_orig = expand('<cword>')")
         line = vim_eval('getline(".")')
         vim_command('normal! diw')
-        if re.match('\w+$', line[cursor[1]:]):
+        if re.match(r'\w+$', line[cursor[1]:]):
             # In case the deleted word is at the end of the line we need to
             # move the cursor to the end.
             vim_command('startinsert!')