Add _since_ info to functions in doc

A few entries are equipped with _since_ information in the docs, but most are not. Such information is quite valuable if working in a multi-version setting.

E.g. I'd like to know which version introduced `Data.Bytestring.Lazy.fromString`, see build failure at
https://matrix.hackage.haskell.org/#/package/tasty-silver/3.0.1.0/ghc-7.4.2@1637957897
```
Test/Tasty/Silver/Interactive.hs:163:15:
Not in scope: `B.fromStrict'
```
I didn't find the necessary information in the changelog.

The _since_ information is somewhat implicitly available from hackage, but tedious to find out manually.