Change COO index matrix to column-major in a format description

Author: mrkn

format/SparseTensor.fbs

@@ -40,14 +40,12 @@ table SparseTensorIndexCOO {
   ///   X[0, 1, 2, 1] := 5
   ///   X[1, 2, 0, 4] := 6
   ///
-  /// In COO format, the index matrix of X is the following 10x4 matrix:
+  /// In COO format, the index matrix of X is the following 4x10 matrix:
   ///
-  ///   [[0, 1, 2, 0],
-  ///    [0, 1, 2, 1],
-  ///    [0, 1, 3, 0],
-  ///    [0, 2, 1, 0],
-  ///    [1, 1, 2, 3],
-  ///    [1, 2, 0, 4]]
+  ///   [[0, 0, 0, 0, 1, 1],
+  ///    [1, 1, 1, 2, 1, 2],
+  ///    [2, 2, 3, 1, 2, 0],
+  ///    [0, 1, 0, 0, 3, 4]]
   ///
   /// Note that the indices are sorted in lexcographical order.
   indicesBuffer: Buffer;