[MINOR][CORE] Fix swapped depth/width formulas in CountMinSketch class doc

[LuciferYang]

What changes were proposed in this pull request?

This PR fixes the class-level Javadoc of org.apache.spark.util.sketch.CountMinSketch, which assigned the two table dimensions to the wrong symbols. The doc previously read:

d = ceil(2 / eps)
w = ceil(-log(1 - confidence) / log(2))

but the implementation (CountMinSketchImpl, the (eps, confidence, seed) constructor) actually sets:

this.width = (int) Math.ceil(2 / eps);
this.depth = (int) Math.ceil(-Math.log1p(-confidence) / Math.log(2));

i.e. width is derived from eps and depth from confidence -- the opposite of what the doc stated. The fix swaps the two lines so the doc matches the code:

w = ceil(2 / eps)
d = ceil(-log(1 - confidence) / log(2))

Why are the changes needed?

Doc fix

Does this PR introduce any user-facing change?

No. Documentation-only change; no behavior, serialization, or API impact.

How was this patch tested?

Pass Github Actions

Was this patch authored or co-authored using generative AI tooling?

Generated-by: Claude Code

[MaxGekk]

LGTM. The corrected formulas match CountMinSketchImpl: width = ceil(2 / eps) and depth = ceil(-log(1 - confidence) / log(2)) (and table = new long[depth][width]). Thanks for the fix!

[MaxGekk]

+1, LGTM. Merging to master/4.x.
Thank you, @LuciferYang.