bug#44239: [PATCH] Python double-digit version detection broken

[Karl Berry]

    https://bugzilla.redhat.com/show_bug.cgi?id=1889732

Well, I found the updated patch from Miro at
https://src.fedoraproject.org/rpms/automake/pull-request/3.patch,
which also fixes m4/python.m4, the crucial change being:

+-    [am_cv_python_version=`$PYTHON -c "import sys; 
sys.stdout.write(sys.version[[:3]])"`])
++    [am_cv_python_version=`$PYTHON -c "import sys; sys.stdout.write('%d.%d' % 
sys.version_info[[:2]])"`])

I presume that's right, though I have no access to any python 3.10
system to check. 

The doc needs some more updating, it seems.  I will commit asap. If you
end up needing to make further changes, please let me know. --thanks, karl.