Make this an error rather than a warning

Author: pfmoore

news/12067.bugfix.rst

@@ -1 +1 @@
-Warn if the ``--python`` option is specified after the subcommand name.
+Fail with an error if the ``--python`` option is specified after the subcommand name.

src/pip/_internal/cli/base_command.py

@@ -138,10 +138,10 @@ def _main(self, args: List[str]) -> int:
         # subprocess, which has the _PIP_RUNNING_IN_SUBPROCESS environment
         # variable set.
         if options.python and "_PIP_RUNNING_IN_SUBPROCESS" not in os.environ:
-            logger.warning(
-                "The --python option is ignored if placed after "
-                "the pip subcommand name"
+            logger.critical(
+                "The --python option must be placed before the pip subcommand name"
             )
+            sys.exit(ERROR)
 
         # TODO: Try to get these passing down from the command?
         #       without resorting to os.environ to hold these.