Proposal for containers: Add 'pop' function to Data.Map

[Tom Ellis]

On Sun, Dec 06, 2020 at 05:19:23PM +0100, Martijn Bastiaan via Libraries wrote:
> Proposal:
> 
>   * Add `pop` and `popWithDefault` to `Data.Map` and `Data.IntMap`.
>   * See https://github.com/haskell/containers/pull/757 for exact definition

Thanks. I wanted this recently! I contented myself with a
lookup/delete pair but your efficient implementation would be better.