feat(ios-swift): add transformer for Color class from SwiftUI

[antoniogamizbadger]

Issue #719

Description of changes:

I have added a new color formatter to correctly render Color from SwiftUI. See the documentation.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

It would be used like this:

  "ios-swift-separate-enums": {
    "transforms": [
      "attribute/cti",
      "name/ti/camel",
      "color/ColorSwiftUI",
      "content/swift/literal",
      "asset/swift/literal",
      "size/swift/remToCGFloat",
      "font/swift/literal"
    ],
    "buildPath": "build/ios-swift/",
    "files": [
      {
        "destination": "StyleDictionaryColor.swift",
        "format": "ios-swift/extension.swift",
        "className": "Color",
        "filter": {
          "attributes": {
            "category": "color"
          }
        }
      },
      {
        "destination": "StyleDictionarySize.swift",
        "format": "ios-swift/extension.swift",
        "className": "CGFloat",
        "filter": {
          "attributes": {
            "category": "size"
          }
        }
      }
    ]
  },

We need to specify the tranformers using transforms because there is not a transform group defined using this new transformer.

[antoniogamizbadger]

I do not know why the linter has deleted all those blank spaces, maybe those markdown files are autogenerated and I should not have updated them. Should I delete those changes?

[chazzmoney]

Very dumb question because I am not familiar enough with swift UI...

Does having 3-digit precision matter significantly? Or would it be more future-proof to enable a longer precision? If so, then maybe a higher value for toFixed() could be worthwhile?

If not, then I think it looks good.

[dbanksdesign]

LGTM! Thank you for this contribution! I think just answering @chazzmoney's question and we should be good to go! (I don't know about those whitespace changes, but its fine)

[dbanksdesign]

Thanks for adding unit tests!

[antoniogamizbadger]

@chazzmoney in my company we never use more than 3 digits, so I think there's not a problem with that.