Close #5602: apidoc: Add `--templatedir` option

doc/man/sphinx-apidoc.rst

@@ -126,6 +126,30 @@ These options are used when :option:`--full` is specified:
 
    Sets the project release to put in generated files (see :confval:`release`).
 
+.. rubric:: Project templating
+
+.. versionadded:: 2.2
+   Project templating options for sphinx-apidoc
+
+.. option:: -t, --templatedir=TEMPLATEDIR
+
+   Template directory for template files.  You can modify the templates of
+   sphinx project files generated by apidoc.  Following Jinja2 template
+   files are allowed:
+
+   * ``module.rst_t``
+   * ``package.rst_t``
+   * ``toc.rst_t``
+   * ``master_doc.rst_t``
+   * ``conf.py_t``
+   * ``Makefile_t``
+   * ``Makefile.new_t``
+   * ``make.bat_t``
+   * ``make.bat.new_t``
+
+   In detail, please refer the system template files Sphinx provides.
+   (``sphinx/templates/apidoc`` and ``sphinx/templates/quickstart``)
+
 Environment
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