Convenience functions for Builder

[andrewthad]

I would like to add the following functions to Data.Text.Lazy.Builder:

toStrictText :: Builder -> Text
unlines :: [Builder] -> Builder
unwords :: [Builder] -> Builder

Additionally, I think that variants of replicate, unfoldr, and unfoldN that work on Builder would be nice to have. I would be happy to implement this.

[andrewthad]

I've written a few of these in text-functions.

[bos]

These sound good, thanks.

[Kleidukos]

@andrewthad Would you be open to have these functions integrated into text ? I can do it.