Added support for visionOS platform

[shadone]

Fixes #1099

[Liquidsoul]

Hi @shadone and thank you for your contribution.

Could you please update the fixtures related to your changes in the stencils? This can be done by running the command:
bundle exec rake generate:output.

You'll also need to rebase and update the location of your changelog entry.

We may also need to add the new platform to this file, but I do not if this is a good idea because I tried to use arm64-apple-visionos1.0 and it seems that you need to install the visionOS SDK as opposed to other SDKs like tvOS and watchOS.
What I mean is that I do not know if the SDK is installed in the CI and this addition would require anyone who want to run the tests locally to install the visionOS SDK 🤔

[AF-cgi]

Any updates?

[djbe]

As mentioned by @Liquidsoul, this PR needs to generate the updated output files, otherwise the tests will fail.