`ReadonlyDeep` / `WritableDeep` not modifying arrays as of TS 5.3.3 about type-fest

[mrazauskas]

I was looking at the issue with ReadonlyDeep. Bisecting tells that the first bad commit is microsoft/TypeScript#54448. Hope that helps.

[gloomweaver]

The issue here is HasMultipleCallSignatures
In 5.2.2 it returned false for Namespace, in current it returns true
You can actually break it 5.2.2 if you provide additional signature in the type

Tried this
HasMultipleCallSignatures<T> extends true ? T & ReadonlyObjectDeep<T> : ((...arguments_: Parameters<T>) => ReturnType<T>) & ReadonlyObjectDeep<T>
But then type of baz is boolean[] & readonly boolean[]
Didn't find a way to pick only signatures from T

[voxpelli]

@trevorade I think the issue is that this repo is using an outdated version of tsd and since tsd ships with its own version of typescript this isn't discovered by it. When updating tsd it does error on this: #839

Hence why we probably should move away from tsd as we talked about in #837