fix docstring so that edgeratio=0 is not boundingbox

[danielsparing]

(the branch is misnamed sorry, this is about the concavehull, not convexhull)

If I understand correctly, ST_Concavehull with edgeRatio=0 does not produce the bounding box, but something that could be described like "vacuum-wrapping" the object. The more precise but more boring description of "maximum concaveness", from the formal definition of JTS.
(In the current tests, the edgeRatio=0.01 does not produce a rectangular, coordinate-aligned bounding box either.)

Related, the ratio itself is not between the convex and concave hull but some fancier ratio related to the Delaunay triangulation.

I suggest for both to take over, the wording from JTS.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (8fa5d6a) 93.86% compared to head (4b4ec85) 93.86%.

Additional details and impacted files

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Files	Coverage Δ
...s/mosaic/expressions/geometry/ST_ConcaveHull.scala	100.00% <ø> (ø)