fix modbus serial event misalingnment

docs/conf_common.py

@@ -1,3 +1,14 @@
+# -*- coding: utf-8 -*-
+#
+# Common (non-language-specific) configuration for Sphinx
+#
+
+# type: ignore
+# pylint: disable=wildcard-import
+# pylint: disable=undefined-variable
+
+from __future__ import print_function, unicode_literals
+
 from esp_docs.conf_docs import *  # noqa: F403,F401
 
 extensions += ['sphinx_copybutton',
@@ -12,8 +23,7 @@ github_repo = 'espressif/esp-modbus'
 # context used by sphinx_idf_theme
 html_context['github_user'] = 'espressif'
 html_context['github_repo'] = 'esp-modbus'
-
-html_static_path = ["../_static"]
+html_static_path = ['../_static']
 
 # Extra options required by sphinx_idf_theme
 project_slug = 'esp-modbus'