message: tfdbg doc: Fix minor typo
diff: @@ -141,7 +141,7 @@ Try the following commands at the `tfdbg>` prompt (referencing the code at
  | **`lt`** | | **List dumped tensors.** | `lt` |
  | | `-n <name_pattern>` | List dumped tensors with names matching given regular-expression pattern. | `lt -n Softmax.*` |
  | | `-t <op_pattern>` | List dumped tensors with op types matching given regular-expression pattern. | `lt -t MatMul` |
  -| | `s <sort_key>` | Sort the output by given `sort_key`, whose possible values are `timestamp` (default), `dump_size`, `op_type` and `tensor_name`. | `lt -s dump_size` |
  +| | `-s <sort_key>` | Sort the output by given `sort_key`, whose possible values are `timestamp` (default), `dump_size`, `op_type` and `tensor_name`. | `lt -s dump_size` |
  | | `-r` | Sort in reverse order. | `lt -r -s dump_size` |
  | **`pt`** | | **Print value of a dumped tensor.** | |
  | | `pt <tensor>` | Print tensor value. | `pt hidden/Relu:0` |
  