Apparently trying to use a direct download link for the git-filter-repo
script results in Windows trying to give the file an unwanted extension.
Warn users about that stupidity.
While at it, also:
* note in the pre-reqs section that we have later hints for Windows
users about installing Python
* provide an additional link for installing Python on Windows that
isn't generic instructions about using Python on Windows but helps
users find the latest python to install from the Microsoft store
Reported-by: Radu Terec <raduterec@gmail.com>
Signed-off-by: Elijah Newren <newren@gmail.com>