Actually document #wontfix

[monkyyy]

As I keep telling people, dont trust the docs; they will 
carefully craft a technically correct but worthless at 
explanation why your code will fail

countUntil and isCallable are ones ive interacted with *NEITHER* 
have a clear explanation why its fundamentally bad

> Counts elements in the given forward range until the given 
> predicate is true for one of the given needles.

Why that sounds like indexOf, herp derp, every user better go 
learn the hardway why it isnt named that. Its SO fun to have an 
off by one error when a user does some unicode while all your 
test cases in ascii work perfectly; every user should get that 
learning experience.

The docs rants useless describing the horrible compromises inside 
the function; not clear descriptions of when it will break *which 
would actually help users*

Bolded `#WONTFIX: countUntil does not provide indexs, and never 
can`

`#WONTFIX: isCallable doesnt untangle templated functions`

`#WONTFIX: delegates dont mix well with loops`

etc etc etc

Being technically correct while pretending it works is worthless.