Release your patch on the same license as the project. The End. Everyone is granted a license to the patch under that license. Nobody can take your code and re-license under a non-compatible license.

"a. Copyright License. You grant Microsoft, and those who receive the Submission directly or indirectly from Microsoft, a perpetual, worldwide, non-exclusive, royalty-free, irrevocable license in the Submission to reproduce, prepare derivative works of, publicly display, publicly perform, and distribute the Submission and such derivative works, and to sublicense any or all of the foregoing rights to third parties. "

The project has a license, just use it.