Fix a couple of minor typos.

Author: larvaboy

core/src/main/scala/org/apache/spark/rdd/PairRDDFunctions.scala

@@ -217,7 +217,7 @@ class PairRDDFunctions[K, V](self: RDD[(K, V)])
    * Return approximate number of distinct values for each key in this RDD.
    * The accuracy of approximation can be controlled through the relative standard deviation
    * (relativeSD) parameter, which also controls the amount of memory used. Lower values result in
-   * more accurate counts but increase the memory footprint and vise versa. Uses the provided
+   * more accurate counts but increase the memory footprint and vice versa. Uses the provided
    * Partitioner to partition the output RDD.
    */
   def countApproxDistinctByKey(relativeSD: Double, partitioner: Partitioner): RDD[(K, Long)] = {
@@ -232,7 +232,7 @@ class PairRDDFunctions[K, V](self: RDD[(K, V)])
    * Return approximate number of distinct values for each key in this RDD.
    * The accuracy of approximation can be controlled through the relative standard deviation
    * (relativeSD) parameter, which also controls the amount of memory used. Lower values result in
-   * more accurate counts but increase the memory footprint and vise versa. HashPartitions the
+   * more accurate counts but increase the memory footprint and vice versa. HashPartitions the
    * output RDD into numPartitions.
    *
    */
@@ -244,7 +244,7 @@ class PairRDDFunctions[K, V](self: RDD[(K, V)])
    * Return approximate number of distinct values for each key this RDD.
    * The accuracy of approximation can be controlled through the relative standard deviation
    * (relativeSD) parameter, which also controls the amount of memory used. Lower values result in
-   * more accurate counts but increase the memory footprint and vise versa. The default value of
+   * more accurate counts but increase the memory footprint and vice versa. The default value of
    * relativeSD is 0.05. Hash-partitions the output RDD using the existing partitioner/parallelism
    * level.
    */