Comment fix for partition_rbound_cmp().

This was an oversight in d363d42b.

Beena Emerson

src/backend/catalog/partition.c

@@ -2128,7 +2128,7 @@ qsort_partition_rbound_cmp(const void *a, const void *b, void *arg)
  * partition_rbound_cmp
  *
  * Return for two range bounds whether the 1st one (specified in datum1,
- * content1, and lower1) is <, =, or > the bound specified in *b2.
+ * kind1, and lower1) is <, =, or > the bound specified in *b2.
  *
  * Note that if the values of the two range bounds compare equal, then we take
  * into account whether they are upper or lower bounds, and an upper bound is