add docstring for SMALL_ALGORITHM

[DanielFrantes]

Part of #52725.

@stevengj

[LilithHafner]

As I mentioned here, we may want to change this alias from InsertionSort to some other algorithm in the future. By adding a docstring that defines SMALL_ALGORITHM as an alias for InsertionSort, you make it a breaking change to later switch to a new default algorithm for small inputs. Anything we write in this docstring must be true now and stay true in all future versions of Julia unless we explicitly mention that it is unstable.

It would be better to say what this constant is for (i.e. it's an alg good for sorting small vectors) and, optionally, say what it is currently defined as, noting that that is subject to change. See ?Base.Sort.DEFAULT_STABLE for an example

help?> Base.Sort.DEFAULT_STABLE
  DEFAULT_STABLE


  The default sorting algorithm.

  This algorithm is guaranteed to be stable (i.e. it will not reorder elements that
  compare equal). It makes an effort to be fast for most inputs.

  The algorithms used by DEFAULT_STABLE are an implementation detail. See extended
  help for the current dispatch system.

  ───────────────────────────────────────────────────────────────────────────────────

Extended help is available with `??Base.Sort.DEFAULT_STABLE`

[DanielFrantes]

So I can say it is am default algorithm for short arreys

[LilithHafner]

yes

[DanielFrantes]

Better now

[DanielFrantes]

Will this PR be marged as one commit to master?

[LilithHafner]

Will this PR be marged as one commit to master?

Yes.

[LilithHafner]

Thanks! This should be ready to merge once CI passes

[DanielFrantes]

You are welcome

[stevengj]

Seems like it could add a bit more explanation, per my suggestion above.

[DanielFrantes]

I will fix it ASAP When I get to the computer