message: Fix a typo in documentation of metadata schema.
diff: @@ -287,7 +287,7 @@ table Content {
  // dimension 1/2: the heatmap image.
  // dimension 3: 17 body parts of a person.
  // Even though the last axis is body part, the real content of this tensor is
  - // the heatmap. "range" should be [min=2; max=3].
  + // the heatmap. "range" should be [min=1; max=2].
  //
  // Case 3: The tensor contains multiple different objects. (Not supported by
  // Content at this point).
  