style: add cmake explanation note

mVento3 · mVento3 · commit d136f2bdffb1 · 2024-06-30T22:04:22.000+02:00
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -1,3 +1,7 @@
+# This file is not used for compiling but used
+# when generating project using CMake generator.
+# If you are not using CMake then just open .sln file
+
 cmake_minimum_required(VERSION 3.22)
 
 project(CppAst.NET CSharp)
