Make all doc fragments, module utils, and plugin utils private (#11896)

* Make all doc fragments private.

* Make all plugin utils private.

* Make all module utils private.

* Reformat.

* Changelog fragment.

* Update configs and ignores.

* Adjust unit test names.

plugins/module_utils/_systemd.py

@@ -0,0 +1,33 @@
+# Copyright (c) 2025, Marco Noce <nce.marco@gmail.com>
+# GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+# Note that this module util is **PRIVATE** to the collection. It can have breaking changes at any time.
+# Do not use this from other collections or standalone plugins/modules!
+
+from __future__ import annotations
+
+import typing as t
+
+from ansible_collections.community.general.plugins.module_utils._cmd_runner import CmdRunner, cmd_runner_fmt
+
+if t.TYPE_CHECKING:
+    from ansible.module_utils.basic import AnsibleModule
+
+
+def systemd_runner(module: AnsibleModule, command, **kwargs) -> CmdRunner:
+    arg_formats = dict(
+        version=cmd_runner_fmt.as_fixed("--version"),
+        list_units=cmd_runner_fmt.as_fixed(["list-units", "--no-pager"]),
+        types=cmd_runner_fmt.as_func(lambda v: [] if not v else ["--type", ",".join(v)]),
+        all=cmd_runner_fmt.as_fixed("--all"),
+        plain=cmd_runner_fmt.as_fixed("--plain"),
+        no_legend=cmd_runner_fmt.as_fixed("--no-legend"),
+        show=cmd_runner_fmt.as_fixed("show"),
+        props=cmd_runner_fmt.as_func(lambda v: [] if not v else ["-p", ",".join(v)]),
+        dashdash=cmd_runner_fmt.as_fixed("--"),
+        unit=cmd_runner_fmt.as_list(),
+    )
+
+    runner = CmdRunner(module, command=command, arg_formats=arg_formats, check_rc=True, **kwargs)
+    return runner