nit

Author: zhengruifeng

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/ColumnResolutionHelper.scala

@@ -561,10 +561,11 @@ trait ColumnResolutionHelper extends Logging with DataTypeErrorsBase {
   //    4, if the matching node is found, but can not resolve the column, also fails with
   //       'CANNOT_RESOLVE_DATAFRAME_COLUMN';
   //    5, resolve the expression against the target node, the resolved attribute will be
-  //       filtered by the output attributes of nodes in the path (from root to matching node);
-  //    6. if more than one resolved attributes are found in the above process, fails with
-  //       'AMBIGUOUS_COLUMN_REFERENCE'.
-  //    7. if the resolved attributes are all filtered out, return the original expression as it is.
+  //       filtered by the output attributes of nodes in the path (from matching to root node);
+  //    6. if more than one resolved attributes are found in the above recursive process,
+  //       fails with 'AMBIGUOUS_COLUMN_REFERENCE'.
+  //    7. if all the resolved attributes are filtered out, return the original expression
+  //       as it is.
   private def tryResolveDataFrameColumns(
       e: Expression,
       q: Seq[LogicalPlan]): Expression = e match {