uniform method naming convention for all lib std containers

[Nick Treleaven]

On Monday, 15 July 2024 at 11:38:43 UTC, Nick Treleaven wrote:
> `canFind` is O(n) in time (need to slice the RBT first to get a 
> range).
> `in` should be defined when the time complexity is better than 
> O(log n).

Sorry, that should be O(log n) or better.