[Backport maintenance/3.3.x] Ref #10260 -- Add documentation for the github output format

doc/user_guide/configuration/all-options.rst

@@ -155,7 +155,7 @@ Standard Checkers
 
 --output-format
 """""""""""""""
-*Set the output format. Available formats are: text, parseable, colorized, json2 (improved json format), json (old json format) and msvs (visual studio). You can also give a reporter class, e.g. mypackage.mymodule.MyReporterClass.*
+*Set the output format. Available formats are: 'text', 'parseable', 'colorized', 'json2' (improved json format), 'json' (old json format), msvs (visual studio) and 'github' (GitHub actions). You can also give a reporter class, e.g. mypackage.mymodule.MyReporterClass.*
 
 **Default:**  ``text``
 

doc/user_guide/usage/output.rst

@@ -8,8 +8,15 @@ Output by default is written to stdout. The simplest way to output to a file is
 with the ``--output=<filename>`` option.
 
 The default format for the output is raw text. You can change this by passing
-pylint the ``--output-format=<value>`` option. Possible values are: ``text``, ``json``,
-``parseable``, ``colorized`` and ``msvs`` (for Visual Studio).
+pylint the ``--output-format=<value>`` option. Possible values are:
+
+* ``text``
+* ``parseable``
+* ``colorized``
+* ``json2``: improved json format
+* ``json``: old json format
+* ``msvs``: visual studio
+* ``github``: `GitHub action messages <https://docs.github.com/en/actions/writing-workflows/choosing-what-your-workflow-does/workflow-commands-for-github-actions>`_
 
 Multiple output formats can be used at the same time by passing
 a comma-separated list of formats to ``--output-format``.

pylint/lint/base_options.py

@@ -102,9 +102,9 @@ def _make_linter_options(linter: PyLinter) -> Options:
                 "metavar": "<format>",
                 "short": "f",
                 "group": "Reports",
-                "help": "Set the output format. Available formats are: text, "
-                "parseable, colorized, json2 (improved json format), json "
-                "(old json format) and msvs (visual studio). "
+                "help": "Set the output format. Available formats are: 'text', "
+                "'parseable', 'colorized', 'json2' (improved json format), 'json' "
+                "(old json format), msvs (visual studio) and 'github' (GitHub actions). "
                 "You can also give a reporter class, e.g. mypackage.mymodule."
                 "MyReporterClass.",
                 "kwargs": {"linter": linter},