bpo-41282: Consistent message and filter warning in setup.py (GH-25571)

Signed-off-by: Christian Heimes <christian@python.org>
diff --git a/Lib/distutils/sysconfig.py b/Lib/distutils/sysconfig.py
index 439040d..aa63093 100644
--- a/Lib/distutils/sysconfig.py
+++ b/Lib/distutils/sysconfig.py
@@ -57,7 +57,7 @@
     from sysconfig import _fix_pcbuild
 
 warnings.warn(
-    'the distutils.sysconfig module is deprecated, use sysconfig instead',
+    'The distutils.sysconfig module is deprecated, use sysconfig instead',
     DeprecationWarning,
     stacklevel=2
 )