Fix incorrect comment in tools/cmake/python_packagecheck.py

Co-authored-by: Hugues Kamba <41612201+hugueskamba@users.noreply.github.com>

tools/cmake/python_packagecheck.py

@@ -1,7 +1,7 @@
 # Copyright (c) 2020 ARM Limited. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
-#file which is invoked by the cmake build system to check if all necessary python packages are installed.
+"""Script to check if a Python module/package is installed."""
 
 import sys
 
@@ -10,4 +10,4 @@ try:
 except ImportError:
     exit(1)
 
-exit(0)
+exit(0)