[MINOR][SQL] Remove out-of-dated comment in CollectLimitExec

### What changes were proposed in this pull request?

This patch removes an out-of-dated code comment that was added by apache#35975.

### Why are the changes needed?

Removed out-of-dated comment to reduce misunderstanding and confusion.

### Does this PR introduce _any_ user-facing change?

No

### How was this patch tested?

Existing test

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

No

Closes apache#45311 from viirya/remove_comment.

Authored-by: Liang-Chi Hsieh <[email protected]>
Signed-off-by: yangjie01 <[email protected]>

Author: viirya

sql/core/src/main/scala/org/apache/spark/sql/execution/limit.scala

@@ -50,11 +50,6 @@ case class CollectLimitExec(limit: Int = -1, child: SparkPlan, offset: Int = 0)
   override def output: Seq[Attribute] = child.output
   override def outputPartitioning: Partitioning = SinglePartition
   override def executeCollect(): Array[InternalRow] = {
-    // Because CollectLimitExec collect all the output of child to a single partition, so we need
-    // collect the first `limit` + `offset` elements and then to drop the first `offset` elements.
-    // For example: limit is 1 and offset is 2 and the child output two partition.
-    // The first partition output [1, 2] and the Second partition output [3, 4, 5].
-    // Then [1, 2, 3] will be taken and output [3].
     if (limit >= 0) {
       if (offset > 0) {
         child.executeTake(limit).drop(offset)