[PATCH RFC 3/3] tools/docs: sphinx-* break documentation bulds on openSUSE

[Mauro Carvalho Chehab <mchehab+huawei@kernel.org>]

Before this patch, building htmldocs on opensuseLEAP works
fine:

    # make htmldocs
    Available Python versions:
      /usr/bin/python3.11

    Python 3.6.15 not supported. Changing to /usr/bin/python3.11
    Python 3.6.15 not supported. Changing to /usr/bin/python3.11
    Using alabaster theme
    Using Python kernel-doc

    ...

As the logic detects that Python 3.6 is too old and recommends
intalling python311-Sphinx. If installed, documentation builds
work like a charm.

Yet, some develpers complained that running python3.11 instead
of python3 should not happen. So, let's break the build to make
them happier:

    # make htmldocs Available Python versions:
      /usr/bin/python3.11

    Python 3.6.15 not supported. Bailing out
    make[2]: *** [Documentation/Makefile:74: htmldocs] Error 1
    make[1]: *** [/root/Makefile:1806: htmldocs] Error 2
    make: *** [Makefile:248: __sub-make] Error 2

It should be then up to the user to figure out a way to make
it work again.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 tools/docs/sphinx-pre-install | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/docs/sphinx-pre-install b/tools/docs/sphinx-pre-install
index 663d4e2a3f57..ecd08e09bae9 100755
--- a/tools/docs/sphinx-pre-install
+++ b/tools/docs/sphinx-pre-install
@@ -1531,7 +1531,7 @@ def main():
 
     checker = SphinxDependencyChecker(args)
 
-    PythonVersion.check_python(MIN_PYTHON_VERSION)
+    PythonVersion.check_python(MIN_PYTHON_VERSION, show_alternatives=True)
     checker.check_needs()
 
 # Call main if not used as module
-- 
2.51.0