tools/docs: check-variable-fonts.py: split into a lib and an exec file

As we'll be using the actual code inside sphinx-build-wrapper,
split the library from the executable, placing the exec at
the new place we've been using:

	tools/docs

No functional changes.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Message-ID: <8adbc22df1d43b1c5a673799d2333cc429ffe9fc.1758196090.git.mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

tools/docs/check-variable-fonts.py

@@ -0,0 +1,23 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0-only
+# Copyright (C) Akira Yokosawa, 2024
+#
+# Ported to Python by (c) Mauro Carvalho Chehab, 2025
+#
+# pylint: disable=C0103
+
+"""
+Detect problematic Noto CJK variable fonts.
+
+or more details, see lib/latex_fonts.py.
+"""
+
+import sys
+
+from lib.latex_fonts import LatexFontChecker
+
+msg = LatexFontChecker().check()
+if msg:
+    print(msg)
+
+sys.exit(1)