Add visionOS extension to platform lists

[amartini51]

Fixes: rdar://119329626

[amartini51]

Force pushed to update the commit message. The Swift 5.9.2 build number is more relevant than a 5.10 build number.

[Kyle-Ye]

As I stated in #225, the open source Swift repo does not accept visionOS on 5.9.2. Is this an expected behavior?

[amartini51]

As I stated in #225, the open source Swift repo does not accept visionOS on 5.9.2. Is this an expected behavior?

I can't speak to whether it's expected compiler behavior that the OSS version of Swift doesn't recognize visionOS as a platform.

However, as stated in the Version Compatibility chapter, TSPL documents the version of Swift as it ships with Xcode. I would expect the differences between open-source versions and Xcode versions of Swift to be minor and temporary. If we see major differences or differences that remain long-term, we should have a larger discussion about how to handle that.

[Kyle-Ye]

However, as stated in the Version Compatibility chapter, TSPL documents the version of Swift as it ships with Xcode.

Got it. Did not notice it before. I used to thought TSPL was aligned with apple/swift