Fix TypeScript error on 'next'

[crutchcorn]

What's Changing and Why

TS tests seem to be failing in #857. I am unable to recreate this issue on my local machine, but I'm hoping this fixes it on CI (I think my local machine simply isn't getting next on TS properly)

What else might be affected

Tasks

• Add tests
• Update Documentation
• Update jimp.d.ts
• Add SemVer Label

Published PR with canary version: 0.9.6-canary.858.667.0

[crutchcorn]

Well golly. I guess it's time to figure out the TS next caching issue on my machine to debug further.

[hipstersmoothie]

We could also try to limit it to not test @next, but I couldn't find that in the docs

[crutchcorn]

We could do that as well, but I'm not able to find a way to test other versions of TS in a range without selecting next either. Let me see if I can't fix this quickly - it'd be a shame if TS3.8 came out and we got a new batch of issues, ya know?

[crutchcorn]

Apologies for taking so long - I found a bug with TS itself that we can't work around that was impacting some type issues. I decided to edge-case that bug while I was already in the weeds of things. That said, this should work for next as well as the other versions. I was able to get the bugs showing on my local machine and they no longer do. Let's hope CI passes

[hipstersmoothie]

This was a super quick response! Thanks for taking a look (and for helping me maintain jimp ❤️ )

[hipstersmoothie]

🚀 PR was released in v0.9.6 🚀