`write(::IO, ::AnnotatedChar)` does not return an Int 

`write` is supposed to return the number of bytes written.

```julia
julia> write(IOContext(Base.AnnotatedIOBuffer()), Base.AnnotatedChar('a', [:y => 2]))

julia> write(IOContext(Base.AnnotatedIOBuffer()), Base.AnnotatedChar('a', [:y => 2])) === nothing
true
```

#53715 will fix this particular case, but not fix the underlying issue with the `write(::IO, ::AnnotatedChar)` method.