Ensure vswhere finds us a single suitable MSVC installation
Also document the numerous arguments to achieve this.
Resolves the issue here where the user had multiple installations: https://forum.openmw.org/viewtopic.php?f=8&t=7386
Also document the numerous arguments to achieve this.
Resolves the issue here where the user had multiple installations: https://forum.openmw.org/viewtopic.php?f=8&t=7386