Generate DocC documentation from the package

[DivineDominion]

Guide at: https://blog.swiftpackageindex.com/posts/auto-generating-auto-hosting-and-auto-updating-docc-documentation/

Change Package

#if swift(>=5.6)
  // Add the documentation compiler plugin if possible
  package.dependencies.append(
    .package(url: "https://github.com/apple/swift-docc-plugin", from: "1.0.0")
  )
#endif

Add manifest

.spi.yml in project root with:

version: 1
builder:
  configs:
    - documentation_targets: [Target]