Add a splice of ShortByteString builder

There is

```haskell
shortByteString :: ShortByteString -> Builder
```

but sometimes we want to write only a part of a SBS, i.e.

```haskell
partOfShortByteString :: Int {- ^ offset -} -> Int {- ^ length -} -> ShortByteString -> Builder
```

as there aren't efficient `take` and `drop` for SBS.

We can go one abstraction lower and provide:

```haskell
byteArray :: ByteArray -> Builder
partOfByteArray :: nt {- ^ offset -} -> Int {- ^ length -} -> ByteArray -> Builder
```

as `ByteArray` is now "the" type, SBS is just a small wrapper around it.

---

If maintainers are happy with an idea, I'll make a PR.