The installer for Windows creates file associations in Tools/msi/launcher/launcher_reg.wxs that identify ".py[w]" files as text/plain.

This is inconsistent with the mimetypes module, which uses text/x-python, and may cause some applications to assume that calling ShellExecute on a .py file will open a text editor rather than executing the script.

We should update the MIME type to text/x-python. This can be backported, as the change is in the launcher and isn't tied to the usual upgrade paths anyway.