Feature/3digithexcodes

[TheMarteh]

fixes #1686

• I have read the Contribution Guidelines
• I have commented on the issue above and discussed the intended changes
• A maintainer has signed off on the changes and the issue was assigned to me
• All newly added code is adequately covered by tests
• All existing tests are still running without errors
• The documentation was modified to reflect the changes OR no documentation changes are required.

Changes

I've added character doubling functionality to the fromHex method if the sanitized string contains exactly 3 characters.
I've also added some tests to confirm the resulting color matches the color when using the 6-digit representation.

I did not update any docs, as the docs of the original fromHex seems adequate to me.

---

Please upvote 👍 this pull request if you are interested in it.

[TheMarteh]

@microsoft-github-policy-service agree

[patriksvensson]

LGTM 👍

[patriksvensson]

Merged! Thank you for your contribution. Much appreciated! 👍

[FrankRay78]

You've stolen another PR from me @patriksvensson! Lucky you're the boss...

[patriksvensson]

Hahaha. I'm NOT the boss! 😁