Fix a typo in a deprecation warning (GH-24423)

diff --git a/Lib/distutils/__init__.py b/Lib/distutils/__init__.py
index 5ddb959..7b2b059 100644
--- a/Lib/distutils/__init__.py
+++ b/Lib/distutils/__init__.py
@@ -13,7 +13,7 @@
 
 __version__ = sys.version[:sys.version.index(' ')]
 
-warnings.warn("The distutils package deprecated and slated for "
+warnings.warn("The distutils package is deprecated and slated for "
               "removal in Python 3.12. Use setuptools or check "
               "PEP 632 for potential alternatives",
               DeprecationWarning)