How to set a higher screen resolution in a Parallels VM

To see a list of the available resolutions, press a key other than `Enter` during the boot loader phase of boot to drop into the boot loader menu, then run `gop list`.


I *believe* that this is the list of available resolutions which the Parallels EFI subsystem presents to the host. For host OS'es that Parallels has custom "Parallels Tools" integrations for (i.e. not FreeBSD, or at least not HelloSystem) Parallels will allow you to resize the host (post-boot) to any resolution you like, but for "unsupported" OS'es I *believe* that this list is everything that is possible.

**One-time resolution selection**
To try a resolution you can do a "one-time" resolution selection by entering `gop set {mode}` (e.g. `gop set 10` to select 1920x1200), then entering `boot` (to boot into the OS).

**Persistent resolution selection**
This took me *hours* to figure out, so I am sharing it here.

Create the file `/boot/lua/local.lua` with the contents:

```lua
loader.perform("gop set 10")
```
(or whatever resolution mode you desire)

**Things that DON'T work**

Putting `exec="gop set 10"` in `/boot/loader.conf` *almost* works, but the resolution almost immediately changes back when the splash screen begins.

Putting `efi_max_resolution="1920x1200"` in `/boot/loader.conf` never had any visible effect for me.

**Updating the docs**
I'd be happy to write a PR for the docs to add this to the Parallels section of the "Getting Started" page. I'm not sure if the info has general applicability to users on any other VMs or real hardware?